Heart Flashcards
a circulatory system contains
muscular pump: heart
fluid: blood
series of conduits: blood vessels
aka CARDIOVASCULAR SYSTEM
birds and mammals have
four chambered hearts and separate pulmonary and systemic circuits
Human heart has
four chambers—
two atria and two ventricles
right ventricle
pumps blood
through the pulmonary circuit
left ventricle
pumps blood through
the systemic circuit
hormones
regulate arterial pressure
epinephrine
released from adrenal medulla in response to a fall in arterial pressure or the
“fight-or flight” response»_space;> arterioles contract
agiotensin
—produced when blood supply to the kidneys fails; reduces flow to peripheral
tissues and directs it to essential organs
Vasopressin, or antidiuretic hormone (ADH)
is released in response to low baroreceptor
activity
(Baroreceptors
receptors sensitive to blood pressure)
Depending on activity of ADH:
The kidneys absorb more water to increase blood pressure,
Or kidneys excrete more water to lower blood pressure.
Bowman’s capsule
site of blood filtration, urine goes through glomeruli
proximal convoluted tube
site of reabsorption of needed substances (proteins, vitamins,
glucose, etc.)
close, bulk transport
loop of henle
site of reabsorption of water and salt
Distal convoluted tube
site of regulation of water, urea, salts, etc.
Distal= far, fine-tuning
Nephron pathway
Blood filtration into Bowman’s capsule
• Reabsorption of needed substances in proximal
convoluted tubule (proteins, vitamins, glucose, etc.)
• Reabsorption of water and salt in the loop of Henle
• Concentration of waste in the distal convoluted tubule
(urea, salts, etc.)
hormones that regulate arterial pressure involved in negative feedback in kidneys:
epinephrine, angiotensin, vasopressin
the kidneys
absorb more water and increase blood pressire
increased baroreceptor activity
inhibits the release of ADH and kidneys excrete more water
negative feedback loops on left
If low arterial pressure (BP): Less stretching in arterial receptors > Hypothalamus releases
ADH > ADH stimulates kidneys to reabsorb water to raise BP ^
negative feedback loops on right
If low arterial pressure (BP): Kidney failure > Kidney releases renin > activates angiotensin to
raise BP ^
positive feedback loop
If low arterial pressure (BP): Adrenal gland secretes epinephrine to raise BP ^
hypothalamus
can stimulate release of antidiuretic hormone (ADH) from the posterior pituitary
ADH
acts on collecting duct cells to insert aquaporins and increase permeability to water.
Rise in blood osmolarity
osmoreceptors in hypothalamus detect an increase in osmolarity and stimulate ADH release
renal excretion of solutes and reabsorption of H2O decrease blood osmolarity
in the kidney: ADH increases permeability of collecting duct cells and distal tubule cells to H2O
rise in blood pressure
stretch receptors in the aorta and carotid artery detect increases in blood pressure and inhibit ADH release
decrease in blood pressure lessens the inhibition and promotes ADH release
Fall in blood pressure
