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341 Cards in this Set
- Front
- Back
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Cell body (aka soma) |
contains nucleus, ER and ribosomes; part of a neuron |
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dendrites |
appendages coming off the soma that receives incoming messages from other cells and sends this to soma |
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axon hillock |
integrator of incoming signals |
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axon |
long structure starts at the axon hillock and ends with nerve terminal(s) |
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myelin |
1. insulation of the electrical signal within a single neuron
2. increases speed of conduction in the axon 3. produced by oligodendrocytes in CNS and Schwann cells in PNS |
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Nodes of River |
small breaks in myelin sheath that exposes the axon membrane critical for rapid signal conduction |
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nerve terminal (synaptic bouton or knob) |
structure is enlarged and flattened to maximize neurotransmission and ensure proper release of neurotransmitters |
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synaptic cleft |
small space between neurons where neurotransmitters are released to bind to dendrite of the postsynaptic neuron
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synapse |
collection of the nerve terminal, synaptic cleft, and postsynaptic membrane |
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tracts versus nerve |
multiple neurons bundled together in PNS = nerve - can be sensory, motor, or mixed in CNS = tracts - only carry one type of information |
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Glial Cells (neuroglia) Types of Glial Cells include: 1. Astrocytes 2. Ependymal cells 3. Microglia 4. Oligodendrocytes and Schwann Cells |
Glial Cells - support and myelinate neurons 1. Astrocytes - nourish neurons and form the blood-brain barrier 2. Ependymal cells produce cerebrospinal fluid (shock absorber) 3. Microglia - phagocytic cells in CNS 4. Oligodendrocytes (CNS) and Schwann cells (PNS) - produce myelin |
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Action Potential in Neurons |
Resting membrane of -70 mV 1. AP triggered if axon hillock received enough excitatory input to be depolarized to threshold (-55 mV to -40 mV) 2. voltage-gated Na+ channels open (from closed state) generating depolarization 3. when Vm nears 35 mV, Na+ channels inactivated and voltage gated K+ channels open --> repolarization then hyperpolarization 4. Na+/K+ ATPase now works to restore resting Vm |
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Na+/K+ ATPase |
maintains a -70 mV resting membrane potential by moving 3 Na+ ions out of the cell for every 2 K+ ions moved into the cell |
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Absolute versus relative Refractory Periods |
absolute = no amount of stimulation can cause another AP to occur relative = greater than normal stimulation required for AP to occur one of the consequences of refractory periods is the uni-directionality of AP |
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Factors impacting conduction |
speed depends on length and CXA of axon (CXA > length) saltatory conduction - hoping effect from node to node due to the Nodes of River potential difference remains constant; intensity of stimulus reflected in frequency of firing |
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Effector |
postsynpatic gland or muscle cell |
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Neurotransmitters |
1. stored in membrane-bound vesicles in the nerve terminal 2. when AP reaches nerve terminal, voltage-gated Ca2+ open 3. increase in intracellular Ca2+ triggers exocytosis of the neurotransmitter |
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What is effect of a neruotransmitters binding to ligand-gated ion channel receptors versus G protein-coupled receptors? |
For ligand-gated, the postsynaptic cell will either be hyperpolarized or depolarized For G protein-coupled receptors, changes in cyclic AMP or an influx of Calcium |
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Methods of Neurotransmitter Regulation |
1. broken down by enzymatic reactions (e.g. acetylcholine by acetylcholinesterase) 2. reuptake carriers bring back to presynaptic neuron (e.g. dopamine and norepinephrine and serotonin use this mechanism) 3. diffuse out of the synaptic cleft (e.g. NO) |
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What are the 3 types of nerve cells?
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1. Sensory (aka afferent neurons) transmit sensory info from receptors to the spinal cord and brain 2. Motor (aka efferent neurons) transmit motor information from the brain and spinal cord to muscles and glands 3. Interneurons (between other two) - most abundant and predominately located in the spinal cord and brain |
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white matter vs. grey matter |
white matter - axons encased in myelin sheaths grey matter - unmyelinated cell bodies and dendrites brain - white matter deeper than grey matter spinal cord - white matter outside cord |
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What are the 4 divisions of the spinal cord? |
1. cervical 2. thoracic 3. lumbar 4. sacral |
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Spinal cord |
protected by the vertebral column motor neurons exit ventrally cell bodies of sensory neurons found in the dorsal root ganglia sensory neurons enter on dorsally |
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Pre-ganglionic and Post-ganglionic neurons |
ANS contains 2 neurons preganglionic neuron is in CNS and its axon travels to a ganglion in the PNS, where it synapses with cell body of the post-ganglionic neuron |
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What is a reflex arc? What is the difference between monosynaptic and polysynaptic reflex arcs? |
reflex arc = nerve pathway that makes immediate response to a stimuli possible monosynaptic - single synapse between sensory neuron and motor neuron (e.g. knee-jerk reflex) polysynaptic - at least one interneuron involved (e.g. withdrawal reflex "stepping on a nail" --> leg flexes (this is monosynaptic) but other leg remains planted to balance (this is the polysynaptic part) |
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Hormones What are the three types of hormones by chemical structure? |
signaling molecules that are secreted directly into the bloodstream to travel to a distant target tissue The three types of hormones by chemical structure are peptide, steroids, and amino acid derivatives. |
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Peptide hormones |
charged; cannot pass plasma membrane so requires an extracellular receptor but travels freely in the bloodstream when peptide hormone binds to its receptor this is considered the first messenger a second signal is triggered called the second messenger There is amplification at each step of the signaling cascade effect is rapid but short-lived |
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Secondary messengers |
responsible for transmission of signal after peptide hormone binds to surface receptor common examples: cAMP, Calcium |
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Steroid Hormones |
derived from cholesterol and produced primarily by the gonads and adrenal cortex easily cross cell membrane and binds to intracellular or intranuclear receptors upon steroid hormone binding, the receptor can directly bind to DNA --> increased or decreased transcription of particular genes effects are slower but longer-lived compared to peptide hormones require carrier proteins to travel through bloodstream |
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Amino Acid-Derivative Hormones |
derived from 1-2 AAs with a few additional modifications e.g catecholamines (epinephrine and norepinephrine) and thyroid hormones (triiodothyronine and thyroxine) catecholamines bind to G protein-coupled receptors are are fast and short-lived thyroid hormones bind intracellularly ad are slow and longer-lived |
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direct vs. tropic hormones |
direct - directly act on target tropic - requires an intermediate and typically originate in the brain OR anterior pituitary gland |
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Endocrine Glands |
pituitary pancreas parathyroid pineal gland gonad (ovaries and testes) hypothalamus adrenal thyroid |
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Hypothalamus |
bridge between the nervous and endocrine systems regulate pituitary gland through tropic hormones release of hormones regulated by negative feedback |
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Hypophyseal portal system |
blood vessel system that directly connects the hypothalamus with the anterior pituitary |
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What is special about prolactin-inhibiting factor (PIF) aka dopamine?
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as long as hypothalamus releases PIF, no prolactin will be released by the anterior pituitary
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Describe the hypothalamic negative feedback mechanism (ACTH and cortisol as the example). |
1. hypothalamus secretes corticotropin-releasing factor (CRF)
2. anterior pituitary secretes adrenocorticotropic hormone (ACTH) in response 3. adrenal cortex secretes cortisol 4. cortisol has a negative feedback on the hypothalamus and anterior pituitary |
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Describe the interactions between the hypothalamus and the posterior pituitary. |
1. neurons in the hypothalamus send axons down the pituitary stalk directly into the posterior pituitary 2. posterior pituitary releases oxytocin and antidiuretic hormone |
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Oxytocin |
hormone from posterior pituitary that stimulates uterine contractions during labor and milk let down during lactation has a positive feedback loop w/ endpoint being delivery |
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Antidiuretic hormone (ADH aka vasopressin) |
secreted by the posterior pituitary in response to low blood volume OR increased blood osmolarity action occurs at the collecting duct in the kidney by increasing permeability to water increased water retention results in increased blood volume and higher blood pressure |
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What are the 7 products of the anterior pituitary? |
FLAT (tropic) PEG (direct) Follicle-stimulating hormone (FSH) on gonads Luteinizing hormone (LH) on gonads Adrenocorticotropic hormone (ACTH) on adrenal cortex Thyroid-stimulating hormone (TSH) on thyroid Prolactin Endorphins Growth hormone (GH) |
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Prolactin |
stimulates milk production in the mammary glands hormone secreted by the anterior pituitary expulsion of the placenta --> dopamine level drops raising the block on milk production |
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Endorphins |
hormone secreted by the anterior pituitary that decreases the perception of pain
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Growth Hormone |
hormone secreted by anterior pituitary that promotes growth of bone and muscle
stimulated by growth-hormone-releasing hormone from the hypothalamus works by preventing glucose uptake in non-growing tissues and stimulating break down of fatty acids |
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What are the three conditions caused by abnormal growth hormone levels? |
In children, excess causes gigantism and deficit causes dwarfism In adults, smaller bones are the primarily affected and results in acromegaly (big hands, feet, and head) |
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Thyroid |
controlled by thyroid-stimulating hormone (TSH) from the anterior pituitary, which is stimulated by TRH (thyroid releasing hormone from the hypothalamus)
located on the front surface of the trachea 2 primary functions 1. setting basal metabolic rate (follicular cells produce T3 and T4) 2. calcium homeostasis (C-cells produce calcitonin) |
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T3 (Triiodothyronine) and T4 (thyroxine) |
both produced by iodination of Tyrosine subscripts represent # of iodines Increased T3 and T4 can lead to increased cellular respiration --> speeds up both synthesis and degradation of protein and fatty acids ` |
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Calcitonin |
decreases plasma calcium levels 1. increased Ca excretion from the kidneys 2. decreased Ca absorption from the gut 3. increased storage of Ca in the bone |
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Parathyroid glands |
4 pea-sized structures that sit on the posterior surface of the thyroid releases parathyroid hormone Main functions of parathyroid hormone 1. raise blood Calcium level (antagonistic to calcitonin) 2. phosphorus homeostasis - reabsorbs phosphate from bone and reduces reabsorption of phosphate from kidney 3. activates Vitamin D |
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Name some functions of Calcium |
bone structure, regulation of muscle contraction, clotting of blood (acts as a cofactor), neurotransmitter release, exocytosis, cell movement |
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Adrenal Cortex |
secretes corticosteroids located on top of the kidneys |
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Corticosterioids |
3 S's salt (mineralocorticoids) sugar (glucocorticoids) sex (cortical sex hormones) |
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Glucocorticoids |
steroid hormones that regulate glucose levels and affect protein metabolism common examples: cortisol and cortisone cortisol and cortisone raise blood sugar by increasing gluconeogenesis and decreasing protein synthesis release from adrenal cortex regulated by CRF --> ACTH pathway |
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Mineralocorticoids |
used in salt and water homeostasis examples include aldosterone |
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Cortical Sex Hormones (androgens and estrogens) |
excessive production can lead to non-genotype specific phenotypic effects |
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Describe the Renin-Angiotensin-Aldosterone System. |
1. decreased blood pressure causes juxtaglomerular cells in the kidney to secrete renin 2. renin cleaves angiotensinogen to active form of angiotensin I 3. angiotensin I converted to angiotensin II by angiotensin converting eznyme (ACE) in lungs 4. Angiotensin II stimuates the adrenal cortex to secrete aldosterone |
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Adrenal Medulla |
located inside the adrenal cortex derived from ectoderm layer produces epinephrine and norepinephrine that are secreted directly into the circulatory system |
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Pancreas |
both exocrine and endocrine functions Islets of Langerhans perform endocrine functions 1. alpha - glucagon 2. beta - insulin 3. delta - somatostatin |
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exocrine vs. endocrine |
exocrine - secretes substances directly into ducts to more superficial tissues; effect is faster acting and shorter lived endocrine - ductless uses extracellular fluid and blood for transportation of hormones; effect is longer lasting and slower |
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Glucagon |
secreted by alpha cells during times of fasting (low blood glucose) and stimulated by GI hormones stimulates degradation of protein and fat and production of new glucose via gluconeogenesis glycogen --> glucose |
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Insulin |
secreted by beta cells during high blood glucose induces muscle and liver cells to take up glucose and store it as glycogen stimulates fat and protein synthesis |
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counterregulatory hormones |
net effect raise blood glucose hormones growth hormone, glucocorticoids, epinephrine, and glucagon |
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Diabetes Mellitus Describe the Two Types |
clinically characterized by hyperglycemia, polyuria, and polydipsia Type I (insulin-dependent) - destruction of beta cells leading to little to no production of insulin Type II (insulin resistant) - receptor level resistance to the effects of insulin |
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Somatostatin |
secreted by delta cells when blood glucose or AA concentration are high inhibitory of both insulin and glucagon secretion also produced by the hypothalamus, where it decreases growth hormone secretion |
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Gonads |
testes secrete testosterone in response to stimulation of gonadotropins (LH and FSH) ovaries secrete estrogen and progesterone in response to LH and FSH |
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Pineal Gland |
located deep within the brain secretes melatonin, which is linked to circadian rhythms |
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Erythropoietin |
produced in the kidney stimulates bone marrow to increase production of erythrocytes in the context of low blood oxygen levels |
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Atrial Natriuretic peptide (ANP) |
functionally antagonistic to aldosterone
lowers blood volume and pressure by promoting the excretion of sodium produced by the heart when atria is stretched from excess blood volume |
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Thymus |
located directly behind the sternum releases thymosin involved in T-cell development and differentiation |
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Vibrissae |
nasal hairs in the nasal cavity, whose function is predominantly filtration |
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Outline the pathway of air through your respiratory system |
enters through nares --> nasal cavity --> pharynx and larynx --> trachea --> bronchi --> bronchioles --> alveolus |
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pharynx vs. larynx |
pharynx is located behind the nasal cavity and is a pathway for both air and food larynx lies below the pharynx and is for air ONLY |
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Larynx --- glottis and epiglottis and vocal cords |
glottis is the opening of the larynx epiglottis covers the glottis during swallowing to prevent food from going down the larynx 2 vocal cords are located in the larynx |
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alveoli (alveolus) |
tiny balloon-like structures where gas exchange occurs coated with surfactant to prevent internal collapse |
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Lung |
bronchi continue to divide into bronchioles then alveoli surround by membranes known as pleurae adjacent membrane is called visceral pleura outer membrane called parietal pleura right lung (3 lobed) > left lung (2 lobed) does not fill passively requires negative pressure for expansion with aid of skeletal muscle |
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Diaphragm |
thin muscular structure dividing the chest cavity from the abdominal cavity under somatic control |
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Intrapleural space |
space between the visceral pleura and parietal pleura typically contains thin layer of fluid aiding in lubrication if excess fluid or air enters intrapleural space open results in atelectasis (lung collapse)
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Describe the stages of ventaliation |
1. inhalation causes increase in thoracic cavity volume -> volume of intrapleural space increases leading to decrease in intrapleural space pressure 2. P in intrapleural space <<< P inside lungs at Patm 3. Lungs expand into the intrapleural space and P lungs decreases drawing air from environment 4. Negative pressure breathing driven by lower relative pressure in the intrapleural space compared to the lungs 5. As chest wall relaxes, lungs recoil --> volume becomes smaller --> pressure increases 6. P lungs > Pair so exhalation occurs |
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Inhalation |
active process use diaphragm and external intercostal muscles to expand the thoracic cavity |
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Exhalation |
does not have to be an active process during vigorous activity, internal intercostal muscles and abdominal muscles pull the rib cage down attributed to recoiling of the lungs |
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Total lung capacity (TLC) |
max volume of air in the lungs with one complete inhale (typically 6-7 liters) |
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Residula Volume (RV) |
min vvolume of air in the lungs after a complete exhale |
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Vital Capacity (VC) |
Difference between max and min volume of air in lungs |
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Tidal Volume (TV) |
volume of air inhaled or exhaled in a normal breath |
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Expiratory Reserve Volume (ERV) Inspiratory Reserve Volume (IRV) |
Volume of additional air that can be forcibly exhaled/inhaled after a normal exhalation/inhalation |
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Regulation Mechanisms of Breathing |
Primarily controlled by ventilation center, which is a collection of neurons in the medulla oblongata ventilation center contains chemoreceptors responsive to carbon dioxide conc. and to extreme hypoxia cerebum to a limited extent can control rate of breathing but it is overridden by the medulla oblongata |
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Gas Exchange |
driven by pressure differential of the gases at alveoli, blood from right ventricle (deoxygenated blood) has high PCO2 and low PO2 both travel down their gradients with no energy expenditure |
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Thermoregulation via vasodilation and vasoconstriction |
as capillaries expand --> more blood passes through --> larger amount of thermal energy dissipates thermoregulation is predominately through capillaries and sweat glands in the skin or rapid muscle contraction |
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Immune defenses of the lungs |
1. vibrissae trap particulate matter and potentially infecitous particles 2. nasal cavity contains lysozyme, which is able to attack the peptidoglycan walls of gram positive bacteria 3. mucus in internal airways trap invaders which can be propelled up the respiratory tract to the oral cavity and expelled or swallowed - mechanism is known as mucociliary escalator 4. mast cells in lungs - release inflammatory signals when antigen binds to surface antibodies --> often mediator of allergic reactions
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Bicarbonate buffer system |
CO2 (g) + H20 (l) -> <- H2CO3 (aq) -> <- H + (aq) HCO3- (aq) |
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Control of pH |
during acidemia, acid-sensing chemoreceptors at BBB send signals to increase the respiratory rate respiratory centers also responsive to the increasing PCO2 and promotes an increase in respiratory rate |
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LAB RAT |
left atrium = bicuspid right atrium = tricuspid |
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Pathway of blood starting with deoxygenated blood |
RA -> tricuspid valve -> RV -> pulmonary valve -> pulmonary artery -> lungs -> pulmonary veins -> LA -> mitral valve -> LV -> aortic valve -> aorta -> arteries -> arterioles -> capillaries -> venules -> veins -> venae cavae -> RA |
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Characteristics of the atria |
thin-walled strucutres that contract to push blood into the ventricles |
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Electrical conduction of the Heart |
sinoatrial (SA) node -> atriovewntricular (AV) node -> bundle of His (AV bundle) -> Prukinje fibers |
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atrial kick |
atrial systole (contraction) causes pressure that forces more blood into the ventricles than passive filling, the additional volume of blood caused by contraction is known as the atrial kick |
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Purkinje fibers |
located at near the apex these fibers help distribute the electrical signal through the ventricular muscle |
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Vagus nerve |
10th cranial nerve responsible for the parasympathetic control of the heart |
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Systole |
ventricles contract, AV valves close (S1), and blood pumped out of ventricles |
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diastole |
heart relaxed, semilunar valves close (S2), blood fills ventricles |
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Cardiac Output |
CO = HR X SV where HR is heart rate and SV is stroke volume |
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EKG |
P-wave = immediately before atria contract QRS complex = before ventricles contract T-wave = ventricular repolarization |
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characteristics of arteries |
highly muscular and elastic creates resistance to blood flow |
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Capillaries |
vessels w/ a single endothelial cell layer allows easy diffusion of gases , nutrients, and wastes |
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Veins |
thin-walled, inelastic vessels that transport blood to the heart
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Name the three portal systems in the body where blood will pass through two capillary beds in series before returning to the heart |
1. hypophyseal portal system - hypothalamus and anterior pituitary before returning to heart 2. hepatic portal system - gut to liver 3. renal portal system - golmerulus -> efferent arteriole -> vasa recta |
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Composition of Blood |
plasma = liquid portion of blood
cellular portion = erythrocytes (RBCs), leukocytes (WBCs), and platelets |
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Erythrocyte |
specialized cell designed for oxygen transport contains hemoglobin which can carry up to 4 oxygens no mitochondria, no nuclei, upon maturation rely completely on glycolysis for the production of ATP |
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Granulocytes (type of WBCs) |
neutrophils, eosinophils, and basophils contain cytoplasmic granules that release contents via exocytosis involved in inflammatory reactions |
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agranulocytes (type of WBCs) |
no cytoplasmic granules lymphocytes (specific immune response) and monocytes |
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Lymphocytes - Difference between B-cells, T-cells |
B-cells mature in lymph nodes or spleen and are responsible for antibiody generation T-cells mature in thymus and kill virally infected cells |
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macrophages What are specific names of macrophages in 1) CNS, 2) skin, and 3) osteoclasts |
monocytes that have exited the bloodstream and entered an organ 1. microglia 2. Langerhans cells 3. osteoclasts |
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Thrombocytes - Platelets |
cell fragments released from megakaryocytes (in the bone marrow) whose function it is to assist in blood clotting |
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Hematopoiesis |
production of blood cells and platelets RBC stimulated by erythropoietin (from kidney) platelet development stimulated by thrombopoietin (from liver and kidney) |
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Erythroblastosis fetalis |
hemolysis of fetal cells during pregnancy due to anti-Rh antibodies crossing the placenta due to prior exposure of Rh- mother to Rh+ fetus |
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Hydrostatic pressure |
F/A blood exerts against the vessel walls pushes fluid out of the bloodstream and into the interstitial space |
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Osmotic (oncotic) pressure |
pressure generated by solutes as they attempt to draw water into the bloodstream |
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Starling forces Why is balance of Starling forces important? |
Starling forces = hydrostatic and oncotic pressures balance is critical for maintaining proper fluid volume and conc. inside and outside of the vasculature |
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Edema |
excess fluid in intersitital space hydrostatic >>>>>> oncotic |
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What happens to part of the interstitial fluid normally?
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Interstitial fluid gets taken up by the lymphatic system and returns to circulatory system via the thoracic duct |
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Clots |
consists of coagulation factors and platelets and prevent/minimize blood loss |
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Describe the coagulation process briefly. |
1. damage to endothelium and collagen and tissue factor are exposed 2. platelets aggregate at the site of injury AND coagulation factors initiate coagulation cascade 3. end point is activation of prothrombin to form thrombin 4. thrombin converts fibrinogen into fibrin 5. net formed that captures RBCs and other platelets forming stable clot 6. clot broken down by plasmin |
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Innate Immunity versus Adaptive Immunity |
Innate Immunity is nonspecific, is always active against infection "first line of defense" Adaptive Immunity is specific, slower to act, and maintain immunological memory of an infection for more rapid response to subsequent exposure |
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B-cells |
produced in bone marrow activated in the spleen to become plasma cells that produce antibodies as part of adaptive immunity when leaving bone marrow considered mature, but naive B-cells |
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Adaptive Immunity |
1. humoral immunity - acts within blood rather than within cells and driven by B-cells and antibiodies 2. cell-mediated immunity driven by T-cells |
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T-cells |
adaptive immune cells that mature in the thymus and coordinates the immune system to directly kill virally infected cells part of the cell-mediated immunity |
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What occurs in lymph nodes with respect to the immune system? |
1. commnicate between immune cells to mount an attack 2. activation of some B-cells |
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Gut-associated lymphoid tissue (GALT) |
immune tissue found in proximity to the digestive system includes tonsils and adenoids, Peyer's patches in small intestine, and lymphoid aggregates in the appendix |
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What is the function of the spleen? |
1. stores blood 2. filters blood and lymph 3. site where immune responses are mounted |
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What is the complement system? Describe the two pathways. |
complement system = proteins in the blood that act as nonspecific defense against bacteria by punching holes in the cell walls of bacteria resulting in osmotic instability 1. classical pathway - binding of antibody to pathogen 2. alternative - does not require antibody |
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Interferons |
proteins (produced by virally infected cells) that prevent viral replication and dispersion by
1. decrease production of viral and cellular proteins in nearby cells 2. decrease the permeability of these cells 3. upregulate MHC class I and MHC class II mlcs |
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Macrophages |
activated when bacterial invader enters a tissue 1. phagocytizzes the invader through endocytosis 2. digests the invader using enyzmes 3. presents little pieces of the invader to other cells using major histocompatibility complex (MHC) 4. release cytokines |
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Cytokines |
chemical substances that stimulate inflammation and recruit additional immune cells to the area |
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Major Histocompatbility Complex (MHC) class I |
displayed by all nucleated cells endogenous pathway that binds antigens from inside the cell |
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MHC Class II |
displayed by professional antigen-presenting cells (e.g. macrophages) exogenous pathway = presents antigens originating outside of the cell |
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Pattern Recognition Receptors (PRR) |
special receptors on macrophages and dendritic cells that can categorize the invader as a bacterium, virus, fungus, or parasite |
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Natural Killer Cells |
type of non-specific lymphocyte detects down regulation of MHC and induces apoptosis of these cells |
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Neutrophils |
most populous leukocyte in blood very short-lived phagocytic and target bacteria using chemotaxis and can detect opsonized bacteria collection of dead neutrophils = pus |
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Eosinophils |
contain bright orange granules primary function in allergic reactions and invasive parasitic infections once activated release histamine (inflammatory mediator) -> vasodilation and increased leakiness of blood vessels allowing immune cells to move into the tissue from the bloodstream |
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basophils |
contain large purple granules that are involved in allergic reactions release large amounts of histamine in response to allergens -> inflammatory response |
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mast cells |
related to basophils but have smaller granules and exist in the tissues, mucosea, and epithelium release large amounts of histamine in response to allergens -> inflammatory response does not leave the bone marrow mature like basophils; only matures at tissue site |
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Humoral Immunity |
production of antibiodies may take as long as a week to reach full effect after initial infection |
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What are the possibilities for antibodies secreted in bodily fluids? |
1. antigen bound, it may attract other leukocytes to phagocytize these antigen immediately 2. agglutination to form large insoluble complexes for phagocytosis 3. neutralize the pathogen |
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What happens when antigen binds to a B-cell? |
activation of that cell -> proliferation and formation of plasma and memory cells
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What happens when antigen binds to antibodies on the surface of a mast cell? |
degranulation (exocytosis of granule contents) allowing the release of histamine and inflammatory response |
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Describe antibody structure. |
Y-shaped mlcs made of two idential heavy chains and two identical light chains held together by disulfide linkages and noncovalent interactions antigen-binding regions at the variable region |
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Describe the mechanism of clonal selection. |
B-cells undergo hypermutation of its antigen-binding region trying to achieve high affinity only those with high affinity survive |
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1. In the absense of exposure of antigen, what does a B cell do? 2. Upon exposure to the correct antigen, what does a B cell do? |
1. naive B-cells wait in lymph node 2. B-cell proliferates into two populations -> plasma cells and memory-B cells this is known as primary response and make take up to 7-10 days to reach full effect |
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memory B-cells |
stay in the lymph node waiting for a reexposure to the same antigen may last a life-time |
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Secondary Response |
memory B-cells when exposed to the same antigen again produced antibiodies specific to that pathogen in a more rapid and robust manner |
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Cell-mediated (cytotoxic) Immunity |
involves T-cells, which undergo positive selection and negative selection positive selection = maturing T-cells that respond to presentation of antigen on MHC negative selection = apoptosis of self-reactive T-cells |
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What are the three major types of T-cells?
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1. helper T-cells (CD4+) 2. Cytotoxic T-cells (CTL or CD8+) 3. Suppressor T-cells |
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Helper T-cells (CD4+) |
1. recruit other immune cells and increase their activity 2. respond to antigens presented on MHC-II mlcs that present exogenous antigens therefore Helper T-cells are most effective against bacterial, fungal, and parasitic infections |
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Cytotoxic T-cells (CD8+) |
1. directly kill virally infected ccells by injection of toxic chemicals 2. respond to antigens presented on MHC-I mlcs that present endogenous antigens so most effective against viral (and intracellular bacterial or fungal) infections |
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Suppressor T-cells |
express CD4 but can be differentiated from helper T-cells because they also express a protein called Foxp3 help tone down the immune response once infection has been adequately contained turn off self-reactive lymphocytes to prevent autoimmune diseases = self-tolerance |
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What is the adaptive immune system response to bacterial (extracellular pathogen infections)? |
1. antigen-presenting cells and macrophages engulf bacteria releasing inflammatory mediators 2. mast cells activated inducing leaky capillaries and immune cells leave bloodstream for tissues 3. dendritic cell leaves affected site and goes to nearest lymph node presenting antigen to B-cells and activate the T-cell response (Helper T-cell) 4. B-cell activation produce antibodies which tag bacteria for destruction 5. plasma cells die, but memory T and B cells survive |
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What is the adaptive immune system response to viral (intracellular pathogen) infections? |
1. infected cell produces interferons thereby reducing permeability of nearby cells, reduce rate of transcription/translation, and cause systemic symptoms 2. MHC-I presents intracellular antigens 3. CD8+ activated if MHC-I is not down-regulated, if it is Natural Killer cells come into play 4. Memory T-cells survive |
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What is the difference between active and passive immunity? |
Active - immune system stimulated to produce antibodies due to exposure to specific pathogen Passive - transfer of antibodies to an individual; transient because plasma cells not transferred |
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Structure of the Lymphatic System |
made of one-way vessels that become larger as they move toward the center of the body carry lymphatic fluid and join to comprise a large thoracic duct in the posterior chest and then into the left subclavian vein bean-shaped structures along the lymphatic vessels are known as lymph nodes |
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Describe 3 main functions of the Lymphatic System. |
1. Equalization of Fluid Distribution - returns some of the interstitial fluid back to the bloodstream 2. Transportation of Biomolecules - transports fats via lacteals into the bloodstream 3. Immunity - place for antigen-presenting cells and lymphocytes to interact and germinal centers in the lymph nodes are where B-cells proliferate and mature |
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Chyle |
lymphatic fluid carrying many chylomicrons |
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Trace the pathway of food through the digestive system. |
oral cavity -> pharynx -> esophagus -> stomach -> small intestine -> large intestine -> rectum |
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Enteric Nervous System |
collection of neurons that govern the GI system |
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oral cavity |
mechanical digestion via mastication Saliva produced by salivary glands aids in chemical digestion |
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Salivary amylase |
hydrolysis of starch into smaller sugars |
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Lipase |
measure of pancreatic function catalyzes the hydrolysis of lipids |
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What are the three parts of the pharynx? |
1. nasopharynx - behind nasal cavity 2. oropharynx - back of the mouth 3. laryngopharynx - above the vocal cords |
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Esophagus |
muscular tube connecting pharynx to stomach upper third is skeletal muscle under somatic control mid and lower third under autonomic nervous system control and a mix of both skeletal and smooth muscle |
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Upper esophageal sphincter |
muscles of the oropharynx where swallowing is initiated |
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lower esophageal sphincter |
muscular ring between the esophagus and stomach that relaxes to allow food passage |
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What are the main anatomical divisions of the stomach starting from the esophageal end?
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1. fundus 2. body 3. pylorus 4. antrum |
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gastric glands What are the three cell types of gastric glands? |
found in fundus and body respond to signals from vagus nerve of PNS 3 cell types 1. Mucous cells 2. Chief cells 3. Parietal cells |
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Mucous cells |
produce bicarbonate-rich mucus (to protect the stomach lining) |
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Chief Cells |
secrete pepsinogen which is cleaved to pepsin by hydrogen ions secreted by parietal cells Pepsin cleaves peptide bonds near aromatic AAs |
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Parietal cells |
secrete HCL secrete intrinsic factor, involved in absorption of Vitamin B12 |
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pyloric glands |
contained mostly in the antrum and pylorus contains G cells that secrete gastrin (peptide hormone) -> induces parietal cells to release more HCl signals stomach contraction which mixes stomach content |
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Chyme |
acidic, semifluid mixture that results after digestion of solid food in the stomach increases SA for maximal absorption of nutrients in the small intestine |
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Name the three segments of the small intestine and their primary functions |
1. duodenum - chemical digestion 2. jejunum - absorption 3. ileum - absorption |
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What occurs in the duodenum? |
1. presence of chyme activates release of brust-border enzymes (break down di/tri into monomers 2. secretes enteropeptidase, which activates other digestive enzymes from the accessory organs |
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Brush-border Enzymes |
present on the luminal surface of the duodenum examples: disaccharidases and peptidases |
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What happens with lack of a particular diasccharidase? |
dissacharide is hydrolyzed by bacteria in the intestines with a byproduct of methane gas undigested disaccharides can have osmotic effect leading to diarrhea |
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Peptidases What is an Aminopeptidase? What size can be reabsorbed? |
Aminopeptidase - secreted by glands in duodenum and removes the N-terminal AA from a peptide di- and tri- peptides can be absorbed across the small intestinal wall |
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Enteropeptidase (aka enterokinase) |
activates trysinogen (a pancreatic protease) to trypsin, which initiates an activation cascade |
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Secretin |
peptide hormone that causes pancreatic enzymes to be released into the duodenum regulate pH by reducing HCl secretion from parietal cells and increasing bicarbonate secretion from the pancreas |
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enterogastrone |
hormone, such as secretin, that slow motility through the digestive tract increasing time for digestion, especially of fats |
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cholecystokinin (CCK) |
secreted in resposne to entrance of chyme in the duodenum stimulates release of both bile and pancreatic juices acts on brain to promote satiety through the ventromedial hypothalamus |
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Bile |
complex fluid composed of bile salts, pigments, and cholesterol |
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Bile Salts |
no direct chemical digestion, but factiliates the checmical digestion of lipids in small intestine, they emulsify fats and cholesterol into micelles which is made accessible to pancreatic lipase soap-like |
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What are the accessory organs of digestion? |
1. pancreas 2. liver 3. Gallbladder |
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Describe the exocrine functions of the pancreas.
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acinar cell produc pancreatic juices, which is a bicarbonate-rich alkaline scretion containing digestive enzymes that digest proteins (peptidases), sugars (amylase), and lipase (fats) |
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Describe the pathway of pancreatic juices to the duodenum |
acrine cells (production)-> pancreatic duct -> duodenum
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What are the major components of bile and their functions?
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1. bile salts - emulsify fats 2. pigment - bilirubin (byproduct of Hemoglobin breakdown). The inability to process or excrete bilirubin results in jaundice 3. cholesterol |
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What structures contribute to the digestion of proteins? |
1. Pepsin in the stomach 2. peptidases (trypsin, chymotrypsin, carboxypeptidases A & B) from the pancreas, digestion occurs in the duodenum 3.dipeptidases and aminopeptidases from the brush border of the small intestine |
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What structures contribute to the digestion of carbohydrates? |
1. amylase in the mouth 2. pancreatic amylase 3. disaccharidases from the brush border in the small intestine |
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Describe the structure and purpose of microvilli |
increase SA for absoprtion of nutrients contain a capillary bed for absorption of water-soluble nutrients AND a lacteal, which is a lymph channel that takes up fats into the lymphatic system |
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How are simple sugars, small nonpolar fatty acids, and AAs absorbed in the small intestine? |
secondary active transport and faciliated diffusion into the epithelial lining epithelial lining -> intestinal capillaries -> liver via the hepatic portal circulation |
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How do larger fats, glycerol, and cholesterol move into the intestinal cells and back into circulation? |
move into the cells separatlely but then reform into triglycerides triglycerides + esterified cholesterol packaged into insoluble chylomicrons chylomicrons -> lacteals -> thoracic duct |
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How are vitamins absorbed? |
Fat-soluble go through chylomicrons to enter the body water-soluble absorbed across endothelial cells into the plasma |
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Components of the large intestine |
three major sections 1. cecum 2. colon 3. rectum |
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Cecum |
outpocketing that accepts fluid exiting the small intestine through the ileoceal valve site of the appendix |
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Colon |
ascending (right), transverse (upper), descending (left), and sigmoid (LLQ) main function is to absorb water and salts from the undigested material from the small intestine forms feces |
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Rectum |
storage site for feces anus = opening for elimination with internal (autonomic control) and external (voluntary control) anal sphincters |
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What are functions of the excretory system? |
1. regulation of blood pressure 2. blood osmolarity 3. acid-base balance 4. removal of nitrogenous wastes |
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Describe the structure of the kidney |
outermost layer is called the cortex with an inner layer called the medulla at the medial surface there is a deep slit called the renal hilum, where the renal artery, renal vein, and ureter enter and exit the kidneys |
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kidney portal system |
enters cortex as afferent arterioles afferent arterioles -> glomeruli -> efferent arterioles -> vasa recta (surround the Hoop of Henle |
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Describe the structure of a nephron. |
glomerulus is surrounded by Bowman's capsule -> proximal convoluted tubule -> descending and ascending loops of Henle -> distal convoluted tubule -> collecting duct |
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Describe the bladder structure. |
muscular lining known as the detrusor muscle, whose contraction is activated by Parasympathetic activity
contains two sphincters 1) internal (involuntary control) urethral sphincter and 2) external urethral sphincter (voluntary control) |
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Process of Urination |
1. stretch receptors convey to the nervous system that bladder requires emptying 2. Parasympathetic neurons fire and detrusor muscle contracts and internal sphincter relaxes 3. relax external sphincter to urinate or maintain sphincter tone to prevent urination |
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Osmoregulation What are the three processes? |
1. Filtration 2. Secretion 3. Resorption |
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Elaborate on Filtration in the kidneys. |
Under most circumstances fluid flows from glomerulus to Bowman's capsule glomerulus acts as a sieve allowing small mlcs to pass but large mlcs to remain in the blood |
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Elaborate on Secretion in the kidneys. |
mechanism for excreting wastes that are too large to pass through glomerular pores salts, acids, bases, and urea directly into the tubule by either active or passive transport |
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Elaborate on Reabsorption in the kidneys. |
solutes from filtrate to blood glucose, vitamins, and AAs are always absorbed unless there is a significant abnormal process ADH and aldosterone can alter water retention to regulate blood pressure |
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Name the layers of the skin working outward from inside. |
hypodermis (subcutaneous layer), dermis, and epidermis |
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The epidermis |
superficial to deep Come, let's get sun burned Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale |
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Stratum basale |
proliferation of keratinocytes, which produce keratin home of melanocytes, which produces melanin |
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Stratum spinosum |
keratinocytes connect to each other home of Langerhans cells (special macrophages) that present antigen to T-cells |
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stratum ganulosum |
keratinocytes die and lose their nuclei |
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stratum lucidum |
only present in thick, hairless skin, such as skin on the sole of the foot or the palms |
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stratum corenum |
several dozen layers of flattened keratinocytes, forming a barrier that prevents invasion by pathogens and prevents loss of fluids and salts |
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melanin
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pigment that serves to protect the skin from DNA damage caused by UV more active melanocytes result in darker skin tones |
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Describe the dermis. |
papillary layer consisting of loose connective tissue reticular layer beneath the papillary layer home of origins of sweat glands, blood vessels, and hair follicles |
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Merkel cells (discs) |
sensory cells present at the epidermal-dermal junction deep pressure and texture sensation within the skin |
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Meissner's corpuscles |
respond to light touch |
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Ruffini endings |
respond to stretch |
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Pacinian corpuscles |
respond to deep pressure and vibration
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Name the methods for achieving thermoregulation |
sweating, piloerection, vasodilation, and vasoconstriction |
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Sweating |
excellent cooling mechanism that is controlled by the autonomic nervous system evaporation of water from the skin absorbs body heat post ganglionic sympathetic neurons utilize acetylcholine |
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Piloerection |
contraction of arrector pili resulting in hairs of the skin to stand up trap a layer of heated air near the skin arterioles constrict |
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Shivering |
rapid contraction of skeletal muscle that requires a sizeable amount of ATP |
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Proximal Convoluted Tubule |
destined for blood: AAs, glucose, water-soluble vitamins, majority of salts, and water
waste: H+, K+, NH3, and urea |
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Descending Loop of Henle |
dives deep into the medulla before turning around permeable only to water, which is reabsorbed into the vasa recta medulla has an ever-increasing osmolarity as you travel deeper into it |
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Countercurrent multiplier system |
flow of filtrate through the loop of Henle is in the opposite direction from the flow of blood through the vasa recta this allows maximal reabsorption of water |
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Ascending loop of Henle |
ascending limb is only permeable to salts and impermeable to water |
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Diluting segment |
part of the ascending loop of Henle that is thicker due to enlarged cells containing large amounts of mitochondria that allow reabsorption of sodium and chloride by active transport only portion of the nephron that can produce urine more dilute than blood |
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Distal convoluted tubule (DCT) |
aldosterone promotes sodium reabsorption with water following it waste: H+, K+, NH3 |
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Collecting duct |
final conc. of urine determine here depending on the permeability of the duct responsive to both aldosterone and ADH point of no return |
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Aldosterone versus ADH |
ADH (peptide) only affects water reabsorption and lowers blood osmolarity Aldosterone (steroid) cause both salt and water absorption and does NOT change blood osmolarity |
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Oncotic versus osmotic pressure
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osmotic pressure draws water into the vasculature and is caused by ALL dissolved particles oncotic pressure - draws water into the vasculature and is caused by dissolved proteins only |
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Characteristics of all muscle types |
innervated capable of contraction, which is reliant on Calcium ions |
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Name the three types of muscles |
1. skeletal 2. smooth 3. cardiac |
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Describe Skeletal muscle |
responsible for voluntary movement thus innervated by the somatic nervous system made of sacromeres, which by microscope appears striated multi-nucleated |
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Describe the two main types of fibers found in skeletal muscle. |
1. Red fibers aka slow-twitch fibers = high myoglobin content and derive their energy aerobically with many mitochondria carrying out oxidative phosphorylation -> Think RED at traffic light
2. White fibers aka fast-twitch fibers = less myoglobin compared to red fibers and therefore lighter in color White is predominate in muscles that contract rapidly but fatigue quickly
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What are characteristics of smooth muscle? |
1. involuntary action innervated by the autonomic nervous system, but can contract without nervous system input (aka myogenic activity by responding directly to stretch or other stimuli) 2. single nuclei 3. contain actin and myosin but no arrangement, so no striations seen 4. more sustained contractions |
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Tonus |
constant state of low-level contraction of smooth muscle often observed in blood vessels |
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Describe Cardiac Muscle ` |
1. primarily uni-nucleated, but can contain 2 nuclei 2. involuntary and innervated by the autonomic nervous system, but striated 3. communication method is a unique characteristic of cardiac muscle |
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Elaborate on the communication process between cardiac myocytes. |
Intercalated discs connecting cardiac muscle cells contain gap junctions through which ions flow directly between the cells coordinated muscle cell depolarization and efficient contraction occurs |
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Sacromere |
basic contractile unit of skeletal muscle made of thick filaments, which are organized bundles of myosin, and thin filaments, which is made of actin, troponin and tropomyosin |
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Divisions of a sacromere |
Z line = defines boundaries M line = middle of the myosin filament I band = thin filaments only H zone = thick filaments only A band = all thick filaments regardless of overlap |
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Myofibrils |
sacromeres attached end-to-end
surrounded by sacroplasmic reticulum (SR) a modified ER with high conc. of calcium ions |
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Sarcolemma |
cell membrane of a myocyte capable of propagating an AP and can distribute the AP to all sarcomeres in a muscle using a system of T-tubules |
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muscle fiber/myocyte |
myofibrils arranged in parallel |
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muscle |
many myocytes in parallel |
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Hemizygous genotype |
only one allele is present for a given gene (such as parts of the X chromosome in males) |
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Penetrance |
percentage of the population with a given genotype who actually express the phenotype |
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Expressivity |
varying phenotypes despite identical genotypes |
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4 Principles of Mendel's First Law: Law of Segregation |
1. Genes exist in alternative forms (aka alleles) 2. organism has 2 alleles for each gene, one from each parent 3. two alleles segregate during meiosis, resulting in gametes that carry only one allele for any inherited trait 4. If two alleles are different, one will be fully expressed and one will be silent. (co-dominance and incomplete dominance are exceptions) Each gamete carries only one allele for a given trait -> result of anaphase I of meiosis |
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Mendel's Second Law: Law of Independent Assortment |
inheritance of one gene does not affect the inheritance of another gene |
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Gene Pool |
all of the alleles that exist within a species |
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Transposons |
small pieces of DNA that insert themselves into another location in the genome |
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Name 4 types of nucleotide-level mutations |
1. silent mutation = no change in AA sequence from a single point mutation 2. missense = change in AA 3. nonsense mutation = STOP codon 4. Frameshift mutation = 1 or more base pair deletions or insertions |
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Name 5 types of chromosomal mutations. |
1. Deletion mutations = large segment of DNA lost from chromosome (note: small segment would be considered frameshift mutation) 2. Duplication mutations = segment copied multiple times in the genome 3. Inversion mutation 4. Insertion mutations = segment of DNA moved from one chromosome to another (if same chromosome = frameshift mutation) 5. Translocation mutations = segment of DNA swapped between 2 chromosomes |
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Genetic leakage
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flow of genes within species such as when hybrid species can reproduce with one/both of the original species |
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Genetic Drift |
changes in the composition of the gene pool due to chance tendency to be more pronounced in small populations |
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Founder Effect |
more extreme case of genetic drift reproductive isolation from other populations as a results of bottlenecks that drastically and suddenly reduce the size of the population available for breeding |
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What is inbreeding and what are the complications associated with it? |
Inbreeding is the mating between two genetically related individuals It encourage homozygosity -> increases prevalence of of certain traits and diseases inbreeding depression = reduced fitness of the population |
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Monohybrid Cross Patterns |
Crossing Two heterozygotes for a trait with complete dominance results in genotype -> 1:2:1 phenotype -> 3:1 |
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Dihybrid Cross Patterns |
Crossing Two Heteroygotes for 2 traits with complete dominance results in phenotype -> 9:3:3:1 For each trait the phenotype ratio 3:1 still holds true |
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Chiasma |
point of crossing over between genes |
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Recombination Frequency |
likelihood that two alleles are separated from each other during crossing over proportional to the distance between the genes on the chromosome |
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Hardy-Weinberg Principle |
1. population is very large (no genetic drift) 2. no mutations that affect the gene pool 3. mating is random (no sexual selection) 4. no migration into or out 5. genes have equal success in producing offspring |
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Hardy-Weinberg Equations |
p + q = 1 p^2 + 2*p*q + q^2 = 1 |
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Natural Selection |
aka survival of the fittest Tenets 1. Not all offspring survive to reproductive maturity 2. chance variations may be heritable; those variations with survival advantage are favorable 3. individuals who inherit more favorable variations have increased fitness fitness = level of reproductive success 3. |
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How does Neo-Darwinsim differ from Darwin's Theory? |
1. Differential reproduction - favorable mutations or recombination gets passed; unfavorable fades out 2. inclusive fitness = success in population 3. punctuated equilibrium - changes in some species occur in rapid bursts rather than evenly over time |
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Describe the 3 modes of natural selection. |
1. stabilizing = selects against extremes
2. directional = emergence and dominance of an initially extreme phenotype 3. disruptive = two extreme phenotype selected over the norm associated term is adaptive radiation, which is the rapid rise of a number of different species from a common ancestor |
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Species |
largest group of organisms capable of breeding to form fertile offspring speciation = formation of new species through evolution |
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Methods of reproductive isolation. |
prezygotic = prevent formation of zygote completely postzygotic = gamete fusion but yields either nonviable or sterile offspring |
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Provide examples of prezygotic mechanisms. |
1. temporal isolation = breeding at different times 2. ecological = different niches within same territory 3. behavioral = lack of attraction 4. reproductive isolation = incompatibility of reproductive anatomy 5. gametic isolation = intercourse can occur, but fertilization cannot |
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Provide examples of postzygotic mechanisms |
1. inviability = zygote that cannot develop to term 2. sterility = offspring cannot reproduce 3. breakdown = first generation can reproduce, but second generation cannot |
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Describe the 3 patterns of evolution. |
1. Divergent = common ancestor with independent development of dissimilar characteristics 2. parallel = related species evolve in similar ways due to analogous environmental selection factors 3. convergent = independent development of similar characteristics not sharing a recent common ancestor |
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What are the three stages of muscle contraction? |
1. initiation 2. Shortening of the Sacromere 3. Relaxation |
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Elaborate on the initiation process of skeletal muscle contraction. |
1. Nervous system communicates with muscles via motor neurons at the neuromuscular junction. 2. acteylcholine released into the synapse binds to sarcolemma receptors inducing depolarization 3. AP induced spreading to the T-tubules & T-tubules travel into muscle tissues to the SR 4. Ca2+ released in SR 5. Ca2+ bind to troponin and induces tropomyosin conformational change, thereby exposing myosin-binding sites on actin filament |
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Elaborate on the shortening process of skeletal muscle contraction. |
Sliding Filament Model 1. myosin with hydrolyzed ATP binds to myosin-binding site on actin 2. Powerstroke occurs driven by dissociation of ADP and inorganic phosphate - sacromere contracts 3. ATP binds to myosin head releasing it from actin 4. ATP is hydrolyzed to ADP + inorganic phosphate and cycle |
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Rigor Mortis |
Post mortem, absence of ATP prevents dissociation of myosin and actin so muscles cannot relax
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Describe the relaxation process of skeletal muscle contraction. |
1. acetylcholinesterase degrades acetylcholine resulting in decaying signal -> sarcolemma repolarizes 2. SR takes up Calcium from sarcoplasm |
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How is overall force of a muscle contraction controlled? |
Strength of response from ONE muscle cell is constant overall force is controlled by the number of motor units the neurons recruit to respond Maximal response = all fibers within a muscle stimulated simultaneously |
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Describe the periods of a simple twitch. |
1. Stimulus 2. Latent period - between reaching threshold and onset of contraction 3. Contraction period 4. Relaxation period |
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Frequency summation vs. tetanus |
Tetanus occurs when frequency of contractions makes it so that muscles are unable to relax at all Frequency summation = combining of frequent contractions for a stronger, more prolonged contraction |
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What are two supplemental energy reserves in muscle for when oxygen is low? |
1. Creatine + ATP -><- Creatine phosphate + ADP 2. anaerobic metabolism via lactic acid production |
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Oxygen Debt |
difference between amount of oxygen needed by muscles and the actual amount present |
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Exoskeletons versus Endoskeletons |
Exoskeletons encase whole organisms and must be shed to accommodate growth Endoskeletons are internal and able to accommodate growth better than exoskeletons |
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Axial versus appendicular skeleton |
axial provides basic central framework and includes the skull, vertebral column, rib cage, and hyoid bone appendicular = bones of the limbs, pectoral gridle, and pelvis |
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Name and contrast the 2 types of bone structures. |
1. compact bone - dense and strong (strength), predominantly makes up the outermost portions of bone 2. spongy/cancellous - lattice structure consisting of trabeculae (bony spicules), predominately makes up internal core of bone |
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Where is bone marrow located and what are the two types of bone marrow? |
Cavities between trabeculae are filled with bone marrow Red marrow = hematopoietic stem cells Yellow marrow = fat and relatively inactive |
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Bone |
connective tissues derived from embryonic mesoderm harder than cartilage but lightweight (relatively) |
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Long bones |
predominately makes up appendicular skeleton characterized by diaphyses (cylindrical shafts) that swell at each end (metaphyses) and terminate (epiphyses) surrounded by periosteum (fibrous sheath) for protection as well as site for muscle attachment |
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Epiphyseal (growth) plate |
sits at the internal edge of the epiphysis
cartilaginous structure serving as site of longitudinal growth during puberty, plate closes and vertical growth is halted |
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Tendons versus ligaments |
tendons attach muscle to bone ligaments attach bones to each other to stabilize joints |
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Haversian Systems or osteons |
functional unit of compact bone |
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Describe a Haversian system. |
contains lamellae (concentric circles of bony matrix surrounding a central microscopic channel) Longitudinal Channels = Haversian canals Transverse Channels = Volmann's canals osteocytes are housed in lacunae (small spaces between the lamellae) |
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What is the function of the Haversian canals and Volmann's canals? |
house the blood vessels, nerve fibers, and lymph vessels that maintain the health of bone connected to lacunae through canaliculi |
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Osteocytes |
mature bone cells |
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Osteoblasts versus osteoclasts |
Osteoblasts build bone Osteoclasts (specialized macrophages) chew bone |
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Name 2 hormones and a fat-soluble vitamin that affects bone metabolism. |
Parathyroid hormone = promotes bone degradation Vitamin D = promote bone degradation to form new stronger bone Calcitonin = promotes bone formation |
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Endochondral ossification |
hardening of cartilage into bone, which is how most of the long bones of the body are formed
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Intramembranous ossification |
undifferentiated embryonic connective tissue transformed into, and replaced by bone (common in skull bones) |
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Describe important characteristics of cartilage in contrast to bone.
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consists of firm but elastic matrix called chondrin, which is secreted by chondrocytes relatively avascular and not innervated advantage over bone is flexibility |
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Joints |
made of connective tissue 2 types 1. immovable 2. movable |
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Immovable joints |
bones fused together to form sutures predominately found in the head |
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Movable joints |
permit bones to shift relative to one another strengthened by ligaments, consisting of synovial capsule that encloses the joint cavity
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Name features of the joint cavity. |
enclosed by synovial capsule, synovium, and articular cartilage contains synovial fluid produced by the synovium for lubrication |
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What is the purpose of the articular cartilage and what disease is associated with its degradation? |
prevent bone on bone impact osteoarthritis |
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Origin vs. Insertion |
origin = end of muscle with a larger attachment to bone insertion = end of muscle with shorter attachment to bone (typically distal connection) |
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antagonistic pairs |
describes how muscles work; one relaxes while the other contracts |
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Flexor versus extensor |
flexor =decreases the angle across the joint extensor =increases or straightens the angle across a joint |
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Abductor versus adductor |
abductor = moves part of body away from the midline adductor = moves part of body toward the midline |
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What are the 3 basic tenets of the cell theory? And the fourth add on? |
1. All living things are composed of cells. 2. Cell is the basic functional unit of life. 3. Cells arise only from preexisting cells. 4. Genetic information carried as DNA and passed from parent to daughter cell |
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Eukaryotic cells versus Prokaryotic cells |
Eukaryotic cells contain a true nucleus, whereas prokaryotic cells do not Prokaryotic cells do not contain any membrane-bound organelles |
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Nucleus |
contains all the genetic material required for replication surrounded by a nuclear envelope with nuclear pores that allow 2 way exchange allows for compartmentalization of transcription and translation |
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Chromosomes |
linear strands of DNA that is woudn around histones (organizing proteins) |
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Nuceolus |
subsection of the nucelus where ribosome RNA (rRNA) is synthesized |
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Mitochondria |
aka power plants of cell two layers - outer and inner membrane contain some of their own genes and replicate independent of the nucleus via binary fission |
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Elaborate on the inner and outer membrane of the mitochondria. |
inner membrane has numerous foldings called cristae, which houses necessary reactants for ETC space between inner and outer is called intermembrane space space inside the inner is called the matrix |
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Lysosomes |
contains hydrolytic enzymes for breakdown of cellular waste products if enzymes are released, triggers autolysis |
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Endoplasmic Reticulum (ER) Smooth vs. Rough |
ER = series of interconnected membranes that is continuous w/ the nuclear envelope Rough ER (RER) = studded with ribosomes for translation Smooth ER (SER) = no ribosomes and used for lipid synthesis, detoxification, and transport of proteins from RER to Golgi Apparatus |
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Golgi Apparatus
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aka packaging center 1. materials from ER (mail man) transferred in via vesicles (mail man car) 2. cellular product modification, sorting, and repackaging (mail room operations) 3. transfer to correct location via vesicles |
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Peroxisomes |
contain hydrogen peroxide for the breakdown of long chain fatty acids via beta oxidation participate in phospholipid synthesis contain enzymes involved in pentose phosphate pathway |
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Name the three components of cytoskeleton |
1. microfilaments 2. microtubules 3. intermediate filaments |
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Microfilaments |
solid polymerized rods of actin involved in muscle contraction, cytokinesis (cleavage furrow) |
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Microtubules |
hollow polymers of tubulin proteins radiate throughout the cell, providing a pathway for motor proteins like kinesin and dynein to carry vesicles |
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Intermediate Filaments |
diverse group of filamentous proteins (e.g. keratin and desmin) high tension sustaining |
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Cilia and Flagella |
motile structures composed of microtubules cilia ar more for movement of materials along the surface whereas flagella are involved in movement of cell itself 9 + 2 structure = 9 pairs forming outer ring with 2 pairs of microtubules in the center 9 + 2 is only seen in eukaryotic organelles of motility |
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Centrioles |
organizing centers for microtubules that is made of 9 triplets of microtubules with a hollow center in mitosis, migrate to opposite poles and organize the mitotic spindle |
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Kinetochores |
complexes that connect chromosomes and microtubules from the centrioles |
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Name the Four Tissue Types |
1. epithelial 2. connective 3. muscle 4. nervous |
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Characteristics of epithelial Tissue |
epithelial cells are joined by layer of connective tissue called the basement membrane constitute the parenchyma (functional parts of organ) polarized with one side facing the lumen (outside world) and one side interacting with blood vessels and structural cells |
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Classification of epithelia by layers |
simple = one stratified = multiple pseudostratified = appear to be multiple but actually one |
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Classification of epithelia by shape |
cuboidal = cube-shaped columnar = long and thin squamous = flat and scalelike |
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Connective Tissue |
supports body ad provides a framework for epithelial cells to carry out their functions contribute primarily to the stroma, or support structure |
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What is a heterozygous advantage? Give a common example. |
being a carrier offers a survival benefit e.g. Sickle Cell Anemia protects some individuals from malaria |
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Define penetrance |
individuals carry a mutant allele but do not show any signs of the disease |
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Define codominance |
contributions of both alleles are visible in the phenotype e.g. pink flowers when red is dominant and white is recessive |
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Elaborate on the 4 main types of RNA. rRNA, hnRNA, mRNA, tRNA |
rRNA is the most abundant form of single stranded RNA that is produced in the nucleolus and important for ribosome functioning hnRNA is premature mRNA that has not gone through any post-transcriptional modifications mRNA is what is read by ribosomes during translation tRNA is the smallest of the RNAs and used to transfer AAs to mRNA during translation |
