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192 Cards in this Set

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What is a plasmid?
Small rings of DNA sometimes present in bacteria that replicate independently of the main chromosome.
Contains genes that allow prokaryotes to survive adverse conditions (antibiotic resistance).
What class of compounds can freely pass through the cell membrane?
Nonpolar, hydrophobic
Peroxisomes
A microbody that contains oxidative enzymes.
Catalyzes rxns that produce hydrogen peroxide.
Breaks down fats and used in liver to detoxify harmful compounds (alcohol).
Glyoxysomes
A microbody usually found in fat tissue of germinating seedlings.
Used to convert fats to sugars.
What are centrioles?
A specialized type of microtubule invovled in spindle organization during cell division.
In animal cells (plant cell do not contain centrioles), located in a region called the centrosome.
What are microtubules?
A component of the cytoskeleton.
Consists of hollow rods composed of polymerized tubulins.
Provides framework for organelle movement w/in the cell.
What are microfilaments?
Solid rods of actin.
Moves materials across the plasma membrane.
What is facilitated diffusion?
passive transport.
The net movement of particles down the concentration gradient w/ the help of carrier molecules.
Diffusion transports what type of molecules
Small, nonpolar molecules such as oxygen, carbon dioxide, and others.
Facilitated transport transports what type of molecules?
Large, nonpolar molecules such as glucose.
Autotrophic organisms store their energy where?
Theyc convert sunlight into bond energy stored in the bonds of organic compounds, chiefly glucose, in the anabolic process of photosynthesis.
The degradative oxidative breakdown of glucose occurs in what 2 steps?
glycolysis
cellular respiration
Glycolysis
Leads to the oxidative breakdown of glucose into 2 molecules of pyruvate, production of ATP, and reduction of NAD+ to NADH.
Regarding glycolysis, pyruvate is further processed in what two ways?
anaerobic conditions - reduced during fermentation to ethanol or lactic acid.

aerobic conditions - oxidized in mitochondria
Alcohol fermentation
Pyruvate (3C) --> Acetaldhyde (2C) --> ethanol (2C)

NAD+ is regenerated when acetaldhyde is reduced by NADH to ethanol, so glycolysis can continue.
Lactic Acid fermentation
Pyruvate (3C) --> Lactic acid (3C)
Cellular respiration, aerobically, can yield how much ATP?
36-38 ATP/glucose molecule
3 stages of cellular respiration (aerobic)
1. pyruvate decarboxylation
2. citric acid cycle
3. electron transport chain
pyruvate decarboxylation
pyruvate formed during glycolysis is transported from cytoplasm to mitochondrial matrix where it is decarboxylated (loses a CO2 and remaining acetyl group is transferred to CoA forming acetyl CoA)
Citric acid cycle
Also Krebs or tricarboxylic acid cycle (TCA)
begins when 2C acetyl group from acetyl CoA combines w/ oxalacetate (4C) forming citrate (6C).
Through a series of rxns, 2 CO2 are released and oxaloacetate is regenerated for use in another cycle.
Electron transport chain
ATP is produced via oxidative phosphorylation when high energy electrons are transferred from NADH and FADH2 to oxygen via carrier molecules.
Without oxygen, what happens in the ETC?
The ETC becomes backlogged w/ electrons. therefore NAD+ can't be regenerated and glycolysis can't continue, unless lactic acid fermentation occurs.
The electron carriers of the ETC are categorized into what 3 protein complexes?
NADH dehydrogenase
b-c1 complex
cytochrome oxidase
In the ETC, one NADH molecule can produce _____ ATP, whereas one FADH2 molecule can produce _______ ATP.
NADH can produce 3 ATP
FADH2 can produce 2 ATP (FADH2 bypasses the NADH dehydrogenase complex, so only 2 energy drops occur = 2 ATP)
What is oxidative phosphorylation?
As hydrogen ions pass through the ATP synthetases, the energy released allows for ADP to be phosphorylated to ATP. The coupling of the oxidation of NADH w/ the phosphorylation of ADP is oxidative phosphorylation
How much energy can be derived from substrate level phosphorylation (glycolysis)
The degredation of 1 glu. molecule yields a net of 2 ATP from glycolysis and 1 ATP for each turn of TCA cycle.
So, a total of 4 ATP are produced by substrate level phosphorylation.
How much energy can be derived from oxidative phosphorylation?
32 ATP
How is fat used as an energy source?
When needed, fats are hydrolyzed by lipases to fatty acids and glycerol and carried to tissues for oxidation.
When fats are needed as an energy source, they are hydrolyzed to fatty acids and glycerol. Glycerol is then converted to what glycolytic intermediate?
PGAL
Eukaryotic cells which contain the diploid (2N) number of chromosomes?
Somatic, or autosomal cells
4 stages of the cell cycle
G1, S, G2, M
Stage of the cell cycle between cell divisions?
Interphase (G1, S, G2)
G1 stage
Presynthetic gap phase.
Cell doubles in size and new organelles are produced.
A cell that proceeds through G1 passes a restriction point and is committed to divide.
Some cells never pass the restriction point and enter a nondividing phase called G0.
Restriction point of cell cycle
When a cell proceeds through G1, it passes this restriction point and is committed to divide.
If not, enters the nondividing phase G0 (skeletal muscle cells and nerve cells)
S stage
Synthesis phase
Each chromosome is replicated.
After replication, chromosomes consists of 2 sister chromatids held together at the centromere.
After DNA replication, cell still contains diploid (2N) number of chromosomes, so cells entering G2 have twice as much DNA as cells in G1.
G2 phase
Postsynthetic gap phase
Cell continues to grow in size and assembly of new oraganelles and cell structures continues.
4 stages of mitosis
Prophase, metaphase, anaphase, telophase
Binary fission
Method of asexual reproduction in which the circular chromosome replicates and a new plasma membrane and cell wall grow inward dividing the cell in to.
Parthenogenesis
Method of asexual reproduction in which an unfertilized egg develops into an adult organism.
Most species of bees and ants
All cells of new organism are haploid.
Parthenogenesis
Method of asexual reproduction in which an unfertilized egg develops into an adult organism.
Most species of bees and ants
All cells of new organism are haploid.
Mitosis is composed of one division resulting in 2 diploid cells. Meiosis comprises _____ divisions resulting in what cells?
2 divisions resulting in 4 haploid gametes
Each meiotic division consists of what 4 stages?
Prophase, Metaphase, Anaphase, Telophase

Same 4 stages as mitosis
Chromosomes that code for the same trait?
Homologous chromosomes
Crossing over
Occurs when chromatids of homologous chromosomes break at corresponding points and exchange equivalent pieces of DNA.
Chiasmata
The point where chromosomes are joined after crossing over has occurred.
Disjunction
Process when homologous pairs separate and are pulled to opposite poles of the cell.
Occurs in anaphase 1
Gonads
Reproductive organs
Sperm being produced in the seminiferous tubules are nourished by what cells?
Sertoli cells
Trace the pathway of sperm
Seminiferous tubules
Epididymus
Vas Deferens
Ejaculatory duct
(Nothing)
Urethra
Penis

SEVEN UP
What is the function of the epididymis?
In the epididymis, sperm acquire motility, mature, and are stored until ejaculation
Seminal fluid is produced by what 3 glands?
Seminal vesicles
Prostate gland
Bulbourethral gland
Trace the path of spermatogenesis
Spermatogonia (2N) -> Primary spermatocytes (2N) -> meiosis 1 -> Secondary spermatocytes -> meiosis 2 -> Spermatids (N) -> Spermatozoa (N)
Follicle cells produce what hormone?
Estrogen
The production of female gametes is known as what?
Oogenesis
Oogenesis occurs where?
The ovarian follicles
Inner layer of an oocyte cell
Zona pellucida
Outer layer of an oocyte cell
Corona radiata
acrosomal process
Tubelike process sperm form to penetrate the cell membrane of the ovum, fusing the sperm and ovum.
Cortical reaction
Triggered by the acrosomal process in the ovum, causes calcium ions to be released into the cytoplasm.
Results when a single zygote splits into 2 embryos.
Monozygotic, or identical twins
Results when 2 ova are released in 1 ovarian cycle and are fertilized by 2 sperm
Dizygotic, or fraternal twins
Chondrocytes
Secrete chondrin, the elastic matrix of cartilage.
Houses mature bone cells (osteocytes)?
Lacunae
Osteoblasts function?
Synthesize and secrete the organic constituents of the bone matrix.
Osteoclasts function?
Break down bone, or bone resorption.
Bone formation occurs by what 2 processes?
Endochondral ossification
Intramembranous ossification
Movable joints are supported and strengthened by what?
Ligaments
Encloses the joint cavity (articular cavity)
Synovial capsule
Skeletal muscle is innervated by what division of the nervous system?
Somatic nervous system
Contractile unit of skeletal muscle
Sarcomeres

Myofibirls are further divided into sarcomeres.
What is the modified endoplasmic reticulum the encloses a myofibril?
Sarcoplasmic reticulum
What is the function of the sarcoplasmic reticulum?
Stores calcium ions
What are red fibers?
Skeletal muscle fibers that have a high myoglobin content and many mitochondria.

Capable of sustained and vigorous activity.

Referred to as "slow-twitch fibers"
What are white fibers?
Skeletal muscle fibers that are anaerobic, so less myoglobin and mitochondria than red fibers.

Have a greater rate of contraction than red fibers, but tire easily.

Referred to as "fast-twitch fibers"
What is a neuromuscular junction?
The link between the nerve terminal and the sarcolemma of the muscle fiber.

Space between the two is the synapse, or synaptic cleft.
What is the role of calcium in muscle contraction?
Action potential is conducted along sarcolemma and T system to interior of muscle fiber.
Causes sarcoplasmic reticulum to release calcium into sarcoplasm
Calcium binds to troponin causing tropomyosin strands to shift, exposing myosin binding sites on actin filaments.
When the muscle contracts, which bands are eliminated?
The H and I bands
What causes rigor mortis
Lack of ATP to relax the muscle.
How does muscle relaxation occur?
When sarcolemmic receptors are no longer stimulated, calcium is pumped back into the sarcoplasmic reticulum.
New ATP binds to myosin head, resulting in dissociation of the myosin from the thin filament.
What is the function of tropomyosin?
Protects actin's binding sites from advances of the myosin head.
In the presence of calcium, troponin moves tropomyosin away, allowing myosin to bind actin the contraction to begin.
What is meant by the all or none response?
Only a stimulus above a minimal value, the threshold value, can elicit contraction.
Individual muscle fibers exhibit an all or none response, but whole muscle does not.
What is a simple twitch?
The response of a single muscle fiber to a brief stimulus at or above the threshold stimulus.

Consists of a laten period, contraction period, and relaxation period.
What is the absolute refactory period?
A brief relaxation period in which the muscle is unresponsive to stimulus.

Followed by the relative refractory period.
What is the relative refractory period.
Following the absolute refractory period, a period during which a greater than normal stimulus is needed to elicit a response.
What is meant by myogenic activity?
A property of smooth muscle in which the muscle can reflexively contract without nervous stimulation.
What is the function of creatine phosphate?
During rest, creatine phosphate is produced when a high energy phosphate is transferred from ATP to creatine.
During exercise, ATP is resynthesized from creatine phosphate and ADP
This molecule can act as an oxygen reserve during strenuous exercise.
Myoglobin
What is myoglobin
A hemoglobin-like protein in muscle tissue.
Has a high oxygen affinity and binds oxygen in the bloodstream.
During strenuous activity, myoglobin releases its oxygen.
This tissue binds epithelium to underlying tissues and holds organs in place.
Loose connective tissue
Two major cell types in loose connective tissue.
Fibroblasts - secretes components of extracellular fibers.

Macrophages - Engulf bacteria and dead cells via phagocytosis.
Dense connective tissue has a high proportion of what type of fibers?
Collagenous fibers
Tendons are formed by what type of tissue?
Dense connective tissue
Ligaments are formed by what type of tissue
Dense connective tissue
Function of tendons?
Attach muscle to bone
Function of ligaments?
Attach bones to joints
Specialized ring of muscle in the lower esophagus that prevents regurgitation of stomach contents into the esophagus.
Cardiac sphincter
Gastric glands in the stomach are composed of what three types of cells?
Chief cells
Parietal cells
Mucous cells
What is the function of chief cells in gastric glands?
Secrete pepsinogen and intrinsic factor, which plays a role in absorbing vitamin B12.
What do parietal cells secrete?
Hydrochloric acid (HCl) which kills bacteria, dissolves the "glue" holding food tissues together, and facilitates the conversion of pepsinogen to pepsin.
What is the function of gastrin?
Secreted by the pyloric glands in the stomach, this hormone stimulates the gastric glands to produce more HCl and stimulates muscular contractions of the stomach, churning food.
What are the 3 divisions of the small intestine?
Duodenum
Jejunum
Ileum
Digestive processes are stimulated and inhibited by what divisions of the nervous system?
Stimulated by the parasympathetic nervous system.

Inhibited by the sympathetic nervous system.
The majority of nutrient absorbtion occurs where?
In the jejunum and ileum of the small intestine.
Ventilation (breathing) is regulated by neurons located where?
In the medulla oblongata
What is vital capacity in reference to respiration?
The maximum amount of air that can be forcibly inhaled and exhaled from the lungs.
What is tidal volume in reference to respiration?
The amount of air normally inhaled and exhaled with each breath.
What is residual volume in reference to respiration?
The amount of air that always remains in the lungs, preventing the alveoli from collapsing.
What is total lung capacity?
The vital capacity plus the residual volume.
The right side of the heart pumps ______ blood into the lungs via the ___________?
Deoxygenated

Pulmonary arteries
What are the 3 portal systems of systemic circulation?
Hepatic portal system
Kidneys
Hypophyseal portal system in the brain.
Trace the path of blood beginning with the superior and inferior vena cavae.
Superior/inferior vena cavae
Right atrium
Right ventricle
Pulmonary artery
Lungs
Pulmonary veins
Left atrium
Left ventricle
Aorta
Oxygenated blood is supplied to the heart by what?
Coronary arteries
What prevents the backflow of blood into the atria?
Atrioventricular valves
What is cardiac output?
The total volume of the blood the left ventricle pumps out per minute.

Cardiac Output = heart rate x stroke volume (volume of blood pumped out the left ventricle per contraction).
Trace the path of electrical impulses in the heart.
SA node
AV node (conducts slowly, allowing atrial contraction and ventricles to fill with blood.)
Impulse then carried by bundle of His (AV bundle) through the Purkinje fibers in the walls of both ventricles
The parasympathetic nervous system innervated the heart via what nerve? What effect does this branch of the nervous system have on the heart?
Vagus nerve.

Decreases heart rate
The sympathetic nervous system innervates the heart via what? What effect does this branch of the nervous system have on the heart?
Cervical and upper thoracic ganglia.

Increases heart rate.
Hormonal control of the heart?
The adrenal medulla exerts hormonal control via epinephrine secretion, which increases heart rate.
How do erythrocytes obtain energy?
The lack mitochondria, therefore they are anaerobic and obtain ATP via glycolysis alone.
3 types of leukocytes?
Granular leukocytes
Lymphocytes
Monocytes
Granular leukocytes
Neutrophils
Basophils
Eosinophils
What leukocyte is involved in specific immune responses?
Lymphocytes
2 types of lymphocytes?
B lymphocytes
T lymphocytes
2 major groups of red blood cell antigens?
ABO group
Rh factor
Type A blood produces _______ antibodies, whereas type B blood produces _________ antibodies.
anti-B
anti-A
Why is type O blood the universal donor?
It posses no surface antigens, so it will not elicit an immune response from the recipient.

Produces both anti-A and anti-B antibodies.
Why is AB blood considered the universal recipient?
It produces neither anti-A or anti-B antibodies.
Why is Rh factor important during pregnancy?
An Rh- woman can be sensitized by Rh+ fetal red blood cells if they enter maternal circulation during birth.
If a future Rh+ fetus is carried by the woman, and anti-Rh antibodies she produced in the first pregnancy can cross the placenta and destroy fetal RBC's, resulting in severe anemia for the fetus, or erthroblastosis fetalis.
What is the Bohr effect?
The allosteric relationship among the concentrations of CO2, H+, and O2.
Increasing concentrations of H+ (decrease in pH) and CO2 (increase in bicarbonate) in the blood decreases hemoglobins O2 affinity.
Thus, high concentrations of H+ and CO2 in active tissue, such as muscle, enhances the release of O2 in this tissue.
Most carbon dioxide in blood is in what form.
Dissolved in plasma as HCO3- (bicarbonate)
Carbon dioxide diffues from tissue into erthrocytes, where it combines with water to form what?
Carbonic acid (H2CO3)
Carbonic acid then dissociates into bicarbonate ion (HCO3-) and a hydrogen ion.
What does carbonic anhydrase do?
Catalyzes both the formation and dissociation of carbonic acid.
The exchange of materials is greatly influenced by what two types of pressure.
Hydrostatic pressure
Osmotic pressure
Describe how hydrostatic pressure and osmotic pressure influence the exchange of nutrients and wastes.
Hydrostatic pressure pushes fluid out of vessels (hydrostatic pressure at arteriole end of capillaries is greater than surrounding tissue, or interstitial fluid).
Osmotic pressure pulls fluid back into vessels (blood has a higher solute concentration than tissue fluid near the venous end of a capillary).
Hydrostatic pressure is dependent on blood pressure driven by the heart.
Osmotic pressure is dependent on solute concentration.
What protein is responsible for osmotic pressure?
Albumin
What is thromboplastin?
A clotting factor released by both platelets and damaged tissue.
Along w/ its cofactors calcium and vitamin K, converts the inactive plasma protein prothrombin to its active form, thrombin.
Summarize the clotting process.
Platelets and damaged tissue release thromboplastin.
Thromboplastin coverts inactive prothrombin to active thrombin.
Thrombin then converts fibrinogen to fibrin, which coats the damaged area and traps blood cells forming a clot.
What are the 2 specific defense mechanisms of the immune system?
Humoral immunity
Cell-mediated immunity
What is humoral immunity?
Produces antibodies following exposure to antigens.
What are antibodies?
Complex proteins that recognize and bind specific antigens and trigger the immune system to remove them.
What lymphocyte is involved in the humoral immune response?
B lymphocytes
How do B lymphocytes, or B cells function?
When exposed to a specific antigen, B lymphocytes specific for that antigen proliferate.
Some become memory cells and others become plasma (effector) cells,
This is known as the primary response.
What is the primary and secondary immune response?
Memory cells and plasma (effector) cells originate from B cells. This is the primary response.
Plasma cells produce and release antibodies.
Memory cells "remember" the antigen and are long lived in the bloodstream. Upons future exposure, memory cells elicit a more immediate response to the same antigen. This is the secondary response.
What is active immunity?
The production of antibodies during an immune response.
Can be conferred by vaccination.
Can requrie weeks to build up.
What is passive immunity?
The transfer of antibodies produced by another organism.
Acquired immediately, but short lived.
What is an example of passive immunity?
During pregnancy, some maternal antibodies cross the placenta and enter fetal circulation, conferring passive immunity to the fetus.
What lymphocyte is involved in cell mediated immunity?
T lymphocytes, or T cells.
What are the different types and functions of T cells?
Cytotoxic T cells - destroy antigens directly.
Helper T cells - activate other B and T cells, as well as macrophages through the secretion of lymphokines.
Suppressor T cells - regulate other B and T cells to decrease their activity against antigens.
What are interferons?
Proteins produced by cells under viral attack.
Inteferons diffuse to other cells, helping prevent the spread of the virus.
What are the primary homeostatic organs in mammals?
Kidneys
Liver
Large intestine
Skin
What is the function of the kidneys?
Regulate the concentration of salt and water in the blood through the formation and excretion of urine.
3 regions of the kidney?
Cortex
Medulla
Pelvis
2 hormones that regulate water reabsorption:
Aldosterone
Antidiuretic hormone (ADH)
What is aldosterone and how does it function in the regulation of water reabsorption?
Aldosterone is a hormone produced by the adrenal cortex.
Stimulates reabsorption of Na+ from the collecting duct and secretion of K+.
Reabsorption of Na+ increases water reabsorption, leading to a rise in blood volume and blood pressure.
Secretion is regulated by renin-angiotensin system.
What is the function of antidiuretic hormone?
Also known as vasopressin, formed in the hypothalamus and stored in the posterior pituitary.
Causes increased water reabsorption.
Acts directly on the collecting duct, increasing its permeability to water.
High solute levels in blood increases ADH secretion.
How do ADH and aldosterone differ?
They both increase water reabsorption in the kidneys, but have different mechanisms.
ADH acts directly on the collecting duct.
Aldosterone indirectly increases water reabsorption by increasing sodium reabsorption from the collecting duct.
How does the liver regulate blood glucose levels?
Glucose and other monosaccharides absorbed during digestion are delivered to the liver via the hepatic portal vein.
Glucose rich blood is processed by the liver, which converts excess glucose to glycogen for storage.
If blood has low glucose level, the liver converts glycogen to glucose and releases it into the blood.
How does the liver process nitrogenous wastes?
Excess amino acids are absorbed in the small intestine and transported to the liver via hepatic portal vein.
Amino acids undergo deamination, in which amino group is removed from the amino acid and converted into ammonia.
Liver combines ammonia with CO2 forming urea, which is excreted by the kidneys.
What are the 5 cellular layers of the epidermis in ascending order?
Stratum basalis, or stratum germinativum
Stratum spinosum
Stratum granulosum
Stratum lucidum
Stratum corneum
The dermis can be subdivided into what 2 layers?
Papillary layer - loose connective tissue
Reticular layer - dense connective tissue
What are tropic hormones?
Hormones which stimulate other endocrine glands to release hormones.
What regulates secretions of the anterior pituitary?
Hypothalamic secretions called releasing/inhibiting hormones or factors.
What are the hormones of the anterior pituitary?
FSH
LH
ACTH
TSH
Prolactin
GH

Think FLAT PiG
What are the functions of GH?
Promotes bone and muscle growth, inhibits the uptake of glucose by certain cells, and stimulates the breakdown of fatty acid, thus conserving glucose.
GH secretion is stimulated by the hypothalamic-releasing hormone GHRH and inhibited by somatostatin.
GH secretion is stimulated by what hormone. What inhibits GH secretion?
Stimulated by the hypothalamic-releasing hormone GHRH.

Inhibited by somatostatin.
What is the function of adrenocorticotropic hormone (ACTH)?
ACTH stimulates the adrenal cortex to synthesize and secrete glucocorticoids.
Regulated by the releasing hormone corticotropin-releasing factor (CRF).
What is the function of TSH?
TSH stimulates the thyroid gland to absorb iodine and then synthesize and release thyroid hormone.
TSH is regulated by thyrotropin-releasing hormone (TRH).
What is the function of Luteinizing hormone (LH)?
In females, LH stimulates ovulation and formation of the corpus luteum.
In males, LH stimulates the interstitial cells of the testes to synthesize testosterone.
LH is regulated by estrogen, progesterone., and gonadotropin-releasing hormone (GnRH).
What is the function of FSH?
In females, FSH causes maturation of ovarian follicles.
In males, FSH stimulates maturation of the seminiferous tubules and sperm production.
FSH is regulated by estrogen and by GnRH.
Describe the posterior pituitary gland
Does not synthesize hormones, but stores and releases the hormones oxytocin and ADH, which are produced by the neurosecretory cells of the hypothalamus.
Hormone secretion is stimulated by AP's descending from the hypothalamus.
What is the function of the hormone oxytocin?
Increases the strength and frequency of uterine muscle contractions during labor.
Stimulates milk secretion in the mammary glands.
What is the function of ADH?
Also vasopressin, ADH increases the permeablility of the nephron's collecting duct to water, thereby promoting water reabsorbtion and increasing blood volume.
Secreted when plasma osmolarity increases, or when blood volume decreases.
What hormones does the thyroid gland produce and secrete?
The thyroid gland produces and secretes thyroxine (T4) and triodothyronine (T3) and calcitonin.
What are the functions of the thyroid hormones?
Thyroxine (T4) and triiodothyronine (T3) are derived from the iodination of the amino acid tyrosine.
Thyroid hormones are necessary for growth and neurological development in children.
Increase rate of cellular respiration and the rate of protein and fatty acid synthesis and degradation in many tissues.
What is hypothyroidism?
Inflammation of the thyroid or iodine deficiency causes hypothyroidism, in which thyroid hormones are undersecreted or not at all.
In children it is called cretinism
What is the function of calcitonin?
Decreases plasma Ca++ concentration by inhibiting the release of Ca++ from bone.
Secretion is regulated by plasma Ca++ levels.
"Think calcitonin tones down Ca++"
What is the function of PTH?
Increases Ca++ concentration in blood by stimulating Ca++ release from bone and decreasing Ca++ excretion in the kidneys.
Converts vitamin D into its active form, which stimulates intestinal calcium absorption.
The adrenal glands consists of what sections?
Adrenal cortex
Adrenal medulla
What hormones does the adrenal cortex secrete?
The steroid hormones, or corticosteroids which are derived from cholesterol
Includes glucocorticoids, mineralocorticoids, and cortical sex hormones.
What are the functions of glucocorticoids?
Secreted by the adrenal cortex, glucocorticoids such as cortisol and cortisone are involved in glucose regulation and protein metabolism.
Raise blood glucose levels by promoting gluconeogenesis and decrease protein synthesis.
Also reduce the body's immunological and inflammatory responses.
Regulated by a negative feedback mechanism.
What are the functions of mineralocorticoids?
Mineralocorticoids, mainly aldosterone, regulate plasma levels of sodium and potassium and consequently, the total extracellular water volume.
Aldosterone causes active reabsorption of sodium and passive reabsorption of water in the nephron resulting in a rise in blood volume and b/p.
Aldosterone stimulates secretion of potassium ion and hydrogen ion into the nephron and their subsequent excretion in the urine.
How is aldosterone secretion regulated?
Regulated by the renin-angiotensis system.
When blood volume falls, the juxtaglomerular cells of the kidney produce renin, an enzyme that converts angiotensinogen to angiotensin I.
Angiotensin I is converted to angiotensin II which stimulates the adrenal cortex to secrete aldosterone which helps restore blood volume by increasing sodium reabsorption at the kidney leading to an increase in water reabsorption.
What hormones does the adrenal medulla produce.
Epinephrine and norepinephrine.

"MEN"
What is the function of epinephrine/norepinephrine?
Epinephrine increases the conversion of glycogen to glucose in liver and muscle tissue causing a rise in blood glucose levels and an increase in the basal metabolic rate.
What are the islets of Langerhans?
Small glandular structures in the pancreas composed of alpha, beta, and delta cells.
Alpha cells produce glucagon.
Beta cells produce insulin.
Delta cells produce somatostatin.
What is the function of glucagon?
Produced and secreted by alpha cells in the pancreas, glucagon stimulates protein and fat degradation, the conversion of glycogen to glucose, and gluconeogenesis, all of which increase blood glucose levels.
Glucagon is antagonistic to insulin.
What is the function of insulin?
Insulin is a protein hormone secreted in response to a high blood glucose concentration.
Stimulates the uptake of glucose by muscle and adipose cells and the storage of glucose as glycogen in muscle and liver cells, thus lowering blood glucose levels.
Stimulates the synthesis of fats from glucose and the uptake of amino acids.
Secretion is regulated by blood glucose levels.
What can cause DM?
Underproduction of insulin or insensitivity to insulin can lead to DM.
What is the function of somatostatin?
Produced and secreted by delta cells in the pancreas, somatostatin decreases both insulin and glucagon secretion
Regulated by CCK and GH levels.
Somatostatin is always inhibitory!!
What is the function of progesterone?
Progesterone is a steroid hormone secreted by the corpus luteum during the luteal phase of the menstrual cycle.
Stimulates the development and maintenance of the endometrial walls in preparation for implantation.
What are the phases of the menstrual cycle?
Follicular phase
Ovulation
Luteal phase
Menstruation
Describe what happens during the menstrual cycle
Follicles mature during the follicular phase via the actions of FSH and LH.
LH surge at midcycle triggers ovulation.
Ruptured follicle becomes corpus luteum and secretes estrogen and progesterone to build up uterine lining in preparation for implantation and also to inhibit GnRH which in turn inhibits LH and FSH.
If fertilization doesn't occur, corpus luteum atrophies, progesterone and estrogen levels fall, menses occurs, and LH and FSH levels begin to rise again.