Midterm #2 Flashcards
how does ADH affect water retention?
- ADH increases the amount of water in the body by causing insertion of water channels called aquaporins in the plasma membrane of the cells forming the kidney tubules
- Water can enter the cells via aquaporins
- Aquaporins allow water in the tubules to enter the cytosol of the kidney cells by osmosis, reducing the amount of water in the tubules
- From the cytosol water into the interstitial fluid and then into blood capillaries
- Net effect of ADH is to return water to the blood that would have otherwise been eliminated from the body as urine - decreases the formation of urine
Anterior Pituitary Hormones (FLAT PiG)
Follicle Stimulating Hormone Luteinizing Hormone Adrenocorticotropic hormone (ACTH) Thyroid-Stimulating Hormone (TSH) Prolactin Growth Hormone (GH)
Prolactin
- Stimulates growth of mammary glands, the initiation and maintenance of milk production
- Suckling of an infant triggers it
Luteinizing Hormone (LH)
- One of two hormones known as gonadotropins
- Stimulate testes (testosterone) and ovaries (estrogen and progesterone)
- Triggers the release of an oocyte (egg)
Follicle Stimulating Hormone (FSH)
- Gonadotropin
- In males: FSH stimulates the testes to produce chemicals that bind and concentrate testosterone
- In females: triggers the production of estrogen, and triggers maturation of ovarian follicles (houses developing oocytes)
Adrenocorticotropic Hormone (ACTH)
- Increased levels of cortisol and aldosterone
- Stimulates the development of the adrenal glands and their synthesis of steroid hormones
short term effects of growth hormone
- Promotion of fat breakdown
- Production of new glucose by the liver
- Inhibition of glucose uptake by muscle fibers
- These effects increase the conc. Of glucose and fatty acids in the blood allowing cells to use them as fuel for growth
which cells produce calcitonin
parafollicular cells
which cells produce parathyroid hormone
chief cells
parathyroid hormone
- increases Ca+ concentration
- Increasing release of calcium ions from bone by stimulating osteoclasts
- Increasing absorption of dietary calcium ions by the small intestine
- Prevent the loss of calcium ions during the formation of urine (Increasing reabsorption of calcium ions from the fluid in the kidney)
- Stimulates calcitriol hormone synthesis in the kidney
calcitonin
- decreases Ca+ concentration
- Calcitonin decreases the blood calcium ion concentration by inhibiting osteoclasts so osteoblasts are unopposed and can build bone (using up calcium from the blood which decreases the blood calcium ion concentration)
3 zones of adrenal cortex
- outer zona glomerulosa
- middle zone fasiculata
- inner zona reticularis
zona glomerulosa
- make mineralocorticoids (aldosterone)
- influence sodium levels
- fluid and electrolyte homeostasis
zona fasiculata
- makes glucocorticoids (hydrocortisone, cortisol)
- influence glucose levels
- metabolic homeostasis
zona reticularis
- makes androgenic steroids (testosterone, estrogen) –> sex hormones
- makes small amount of glucocorticoids (cortisol)
aldosterone
- Maintaining the concentration of extracellular sodium and potassium ions within their normal ranges
- Regulating extracellular fluid volume
- Maintaining blood pressure
- Maintaining acid-base homeostasis (maintains the pH of the blood)
Activates hydrogen ion pumps in kidney tubules which transports hydrogen ions from the extracellular fluid into the fluid in the tubules, which is excreted as urine. This lowers the hydrogen ion concentration, which increases pH of the blood to its normal alkaline level. (this is why urine is acidic)
cortisol
- help mediate the body’s response to stress through the regulation of blood glucose
- Effects of cortisol (primary target tissues: liver, muscle, adipose)
- Gluconeogenesis (glucose molecule production) in the liver → increases blood glucose
- Release of amino acids from muscle tissue (skeletal muscle breakdown) → can be converted to glucose by gluconeogenesis
- Release of fatty acids from adipose tissue → can be converted to glucose
- Also acts as an anti-inflammatory agent by decreasing levels of leukocytes (inflammatory cells)
androgenic steroids (sex hormones)
- Androgenic steroids - sex hormones that affect reproductive organs, or gonads
- Majority of androgenic steroids are produced by gonads but they are also synthesized in small amounts by adrenal cortex
- Can be converted to testosterone or estrogen
hormones of the adrenal medulla
- catecholamines (norepinephrine & epinephrine)
Increase rate and force of heart contractions
Dilating the bronchioles
Constricting blood vessels supplying the skin, digestive organs, and urinary organs
Dilating blood vessels supplying skeletal muscles
Dilating pupils
Decreasing digestive and urinary functions
cells of the adrenal medulla that make catecholamines
- chromaffin cells
delta cells
- secrete somatostatin
- inhibits pancreatic hormone secretion
what hormones does the thymus gland produce
- thymosin
- thymopoietin
progesterone
- Progesterone production peaks after ovulation and during pregnancy (pro=for)
- Progesterone helps prepare the body for pregnancy and support fetal development
- Target tissue: smooth muscle, body temperature, blood clotting, metabolism, bone tissue
Atrial Natriuretic Peptide (ANP)
- released in response to stretch sensitive ion channels opening more widely (increased blood volume)
- Triggers relaxation of smooth muscle cells in blood vessels (vasodilation) → enhances excretion of sodium ions from kidneys (natriuresis) (and water excretion) → lower blood volume → decrease blood pressure
Erythropoietin (EPO)
- Secreted by the kidney in response to a decreased level of oxygen in the blood
- EPO acts on red bone marrow where it stimulates the development of erythrocytes, which increases the oxygen carrying capacity of blood
cardiac tamponade
Penetrating wounds of the pericardium/heart
Bleeding (or fluid) occurs into the pericardial cavity
Compression of heart
Circulation is greatly compromised
Veins of the face and neck become engorged owing to compression of the SVC as it enters the inelastic pericardium
Beck triad - collection of the clinical signs of cardiac tamponade
- low blood pressure (weak pulse)
- muffled heart sounds
- distended neck veins
the great vessels
- superior and inferior vena cava
- pulmonary trunk
- pulmonary veins
- aorta
right coronary artery
splits into:
- right marginal artery
- posterior interventricular artery
left coronary artery
splits into:
- anterior inter ventricular artery
- circumflex artery
coronary veins
- great cardiac vein
- small cardiac vein
- middle cardiac vein
pacemaker cell action potentials
- slow initial depolarization
- full depolarization
- repolarization
- minimum potential phase
conduction of action potentials through the heart
1) The SA node generates an action potential, which spreads to atrial cells (via gap junctions) and the AV node
2) After the AV node delay (time it takes for the ap to spread from the SA node to the AV bundle), the action potential is conducted to the AV bundle and then to the right and left bundle branches
3) The action potential spreads from the bundle branches along the purkinje fibers to the contractile cells of the ventricles
contractile cells action potentials
- rapid depolarization
- initial repolarization
- plateau phase
- repolarization
P-R interval
atrial depolarization + AV node delay
Q-T interval
entire duration of a ventricular action potential
S-T segment
ventricular plateau phase
events of cardiac cycle
1) ventricular filling phase
2) isovolumetric contraction phase
3) ventricular ejection phase
4) isovolumetric relaxation phase
3 factors that influence stroke volume
- The preload imposed on the heart before it contracts
- The heart’s contractility (ability to generate tension)
- The afterload against which the heart pumps as it contracts
frank starling law
the more the ventricular muscle cells are stretched (more blood enters the ventricle/greater preload) the more forcefully they contract
Chronotropic agents
factors that influence the rate at which the SA node depolarizes