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76 Cards in this Set
- Front
- Back
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What are the 2 main control systems?
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Nervous
Endocrine |
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What are a few differences between the nervous and endocrine systems?
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Nervous - rapid response via action potentials and neurotransmitters, controlled consciously or subconsciously
Endocrine - slower more prolonged response,uses hormones and feedback loops |
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If we cut the cerebrum in half what can you see?
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the Cerebral cortex
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Explain the cerebral cortex
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2-4mm of grey mater
follows contour or gyri and sulci increases amount of grey mater for given area conscious thought and recognition of stimuli |
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What are the steps in sensory response?
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receptor
sensory/afferent neuron CNS for integration spinal cord - sensory tracts brain - cerebral cortex, parietal/occipital/temporal lobe conscious awareness of stimuli |
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What are the steps in motor response?
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cerebral cortex - conscious decision to move, frontal lobe
spinal cord - motor tracts descending motor -efferent |
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How does the sensory enter the spinal cord?
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via the dorsal nerve root
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How does the motor exit the spinal cord?
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via the ventral nerve root
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Spinal cord tracts are either....
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ascending or descending
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Ascending is associated with what?
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sensory
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Descending is associated with what?
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motor
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What do the tracts of the spinal cord do?
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take info up or down the spinal cord
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Where does the spinothalamic tract take info?
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spinal cord to the thalamus
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Where does the corticospinal tract take info?
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cerebral cortex to spinal cord
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Where does the Spinocerbellar tract take info?
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Spinal cord to cerebellum
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What is a reflex?
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involuntary response to a stimuli
rapid, predictable and unlearnt uses a specific neural pathway minimal processing cannot be improved by repetition |
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What is the neural pathway a reflex takes?
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reflex arc
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What is a reaction?
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voluntary response to stimuli
slower, lots of neural processing not predictable can be improved with practice |
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What are the 5 basic components to a reflex arc?
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1. sensory receptor detects stimuli
2. sensory neuron conducts action potentials through nerve and dorsal root of SC 3. in the SC sensory neuron synapses with an interneuron 4. the interneuron synapses with a motor neuron 5. a motor neuron axon conducts action potentials through the ventral root and SN to the effector organ |
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What are the 2 classifications of reflexes?
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Somatic
Autonomic |
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What is a monosynaptic
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one synapse
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What is a polysynaptic?
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a synapse with one or more interneurons
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What muscle do Somatic reflexes deal with?
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skeletal muscle
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What is the purpose of somatic reflexes?
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remove body from painful stimuli
keep balance SC or brain as the integration center |
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What are the names of a few somatic reflexes?
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Stretch reflex
Golgi tendon reflex withdrawal reflex crossed extensor reflex |
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What do autonomic reflexed involve the control of?
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smooth muscle
cardiac muscle body viscera |
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What is autonomic reflex used for?
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maintaining body function e.g. HR, BP blood CO2 levels
movement of food through gut defecation and micturition reflex |
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The brainstem is composed of 3 parts, name them
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Medulla Oblongata
Pons Midbrain |
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Damage to the brainstem can cause death, T or F?
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True
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explain the medulla oblongata
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Most inferior part of brainstem and is a continuation of SC
lots of white matter - ascending and descending tracts lots of nuclei for integration - regulates HR, BVD, respiratory, hiccups, coughing, sneezing, swallowing, vomiting |
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explain the pons
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bridge between medulla/midbrain and cerebellum
sleep centre for REM pontine respiratory centre |
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explain the midbrain
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between the pons and diencephalon
has important nuclei for movement reflex areas include superior and inferior colliculli |
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What is superior colliculli for?
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visual, coordinates head and eye movements
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What is inferior colliculli for?
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auditory, startle reflex turn head towards sound
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What are the 3 parts to the diencephalon?
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Thalamus
Hypothalamus Epithalamus |
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explain the hypothalamus
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important in homeostatic mechanisms
autonomic control, regulates body temp, sleep-wake cycles, food intake, water balance and thirst regulates pituitary secretions |
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The hypothalamus is the link to the endocrine system through which gland?
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pituitary gland
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What is the pituitary gland joined to the hypothalamus by?
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infundibulum or pituitary stalk
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how many parts is the pituitary gland divided into?
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2
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How big is the pituitary gland?
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pea size
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What are the 2 parts of the pituitary gland called?
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Anterior - (adenohypohysis) grows from roof of mouth and made from glandular cells
Posterior - (Neurohypophysis) down growth from brain is neural tissue |
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explain the Anterior pituitary (AP) in more detail
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made from glandular tissue
secretes 7 hormones in response to releasing/inhibiting hormones from hypothalamus releasing factors travel to AP via a network of capillaries called hypothalamohypophyseal portal system this stimulates cells in AP to secrete hormones into blood |
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What are the 7 hormones of the AP and what are their target tissue?
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Growth Hormone (GH) - most body tissue
Thyroid stimulating hormone (TSH) - thyroid gland Andrenocorticotropic Hormone (ACTH) - Adrenal gland cortex only Follicle stimulating Hormone (FSH) - Ovaries and testis Luteinizing Hormone - ovaries and testis Prolactin - Ovaries and mammory glands Melanocyte-stimulating hormone (MSH)- skin cells |
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How many hormones does the Posterior Pituitary (PP) secrete?
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2, hormones made in cell bodies located in hypothalamus are transported down middle of axons to be released from PP in a process called neural secretion
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axons tract down through what?
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infundibulum/ pituitary stalk
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What is this tract of axons called?
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hypothalamohypophysial tract
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Where are the PP hormones made?
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in the hypothalamus
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What are the 2 main groups of cell bodies in the hypothalamus?
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Supraoptic nuclei
paraventricular nuclei |
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explain the supraoptic nuclei
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above optic chiasma
produces antidiuretic hormone (ADH) stimulates kidneys to retain H2O |
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explain the paraventricular nuclei
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parallel to ventricles
produce oxytocin influence on smooth muscle, uterus and mammary glands |
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What are the 3 types of communication for the endocrine system?
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Autocrine
paracrine Endocrine |
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What cells do the autocrine cells affect?
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same cells that secrete them
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What cells do the paracine cells affect?
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nearby cells
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What cells do the endocrine cells affect?
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cells distant to source
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what is the differnce between endocrine and exocrine glands?
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endocrine glands are ductless
exocrine have ducts to secrete non hormonal products |
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What are the 3 types of chemical hormones?
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amino acid based
steroid based eicosanoids |
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explain which chemical hormones are water soluble and where they are made
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Amino acid based - water soluble exempt hormones secreted by thyroid gland, made from AA, peptides, protein
Steroid based - lipid soluble, made from cholesterol Eicosanoids - lipid soluble, made from fatty acids |
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What does the chemical composition determine?
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how they are transported
how they affect target tissue |
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explain water soluble hormones
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dissolve in plasma
travel as free hormones degrade rapidly have short half life |
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explain lipid soluble hormones
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must bind to protein
keeps confined in blood process of binding is reversible, releases hormone in the tissues where needed |
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Hormones attach to receptors or ____________ of their target cells
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binding sites
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Where can receptors be?
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inside the cell
on the membrane of target cell |
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What are the 3 things that hormones and change/activate?
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change the activity of the organelles - increase production of mitochondria/ribosomes
change the cell membrane permeability - increase uptake of something activate a particular cell mechanism - increase/decrease production |
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How do we get changes to occur in the cell?
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indirectly - via cell mediator/second messenger
directly - influencing DNA |
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Which method is used depends on the what of the hormone?
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membrane solubility
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What method do non lipid soluble hormones have to use?
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indirect as can't get through lipid bilayer of membrane
e.g. most AA and proteins |
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What method do lipid soluble hormones have to use?
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direct
e.g steroids, thyroid hormones |
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explain the indirect method of hormone action- second messenger mechanism.
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Hormone is the first messenger outside cell
cell has receptors on outside of membrane hormone attaches to receptor activates G protein Adenyl-cyclase converts ATP------>cAMP cAMP acts as second messenger cAMP is degraded and effects stop to continue need more hormone NON LIPID SOLUBLE |
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explain direct messenger mechanism
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hormone can get through membrane
attatches to receptor inside cytoplasm both hormone and receptor complex pass nucleus activates specific genes steroid hormones |
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What are the 3 stimuli that control hormone release?
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Humoral stimuli
Neural stimuli Hormonal stimuli |
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explain humoral stimuli
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secrete in direct response to changing blood levels
e.g parathyroid (Ca++) |
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explain neural stimuli
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nerves can directly stimulate
less common e.g. adrenal medulla (sympathetic) |
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explain hormonal stimuli
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in response to hormones by other endocrine organs
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explain negative feedback loop
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as concentration of Y increases this feedbacks to gland B which in turn increases the secretion of hormone X which reduces the levels of Y. a rising level of Y triggers the response to reduce levels of Y
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Do most hormones use a negative feedback loop?
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Yes
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explain positive feedback loop
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hormone secretion continues when increase levels of hormone/substance
reinforces the secretion and therefore reinforces effect e.g. labor, milk ejection, blood clotting |
