RAT 8 Flashcards
(46 cards)
why is blood pressure so tightly regulated?
in order to constantly meet the body’s blood flow needs
which branch of the nervous system is primarily responsible for changes in blood pressure?
autonomic nervous system (sympathetic and parasympathetic NS)
describe how the sympathetic changes leads to changes in blood pressure.
- increase in heart rate and contractility which leads to increased cardiac output
- vasoconstriction of arterioles which increases peripheral resistance
which hormones are released onto the target organs in the sympathetic NS?
- epinephrine
- norepinephrine
describe how the parasympathetic nervous system leads to changes in blood pressure.
- slows heart rate, mild effect on contractility which decreases cardiac output and blood pressure
- vasodilation and decrease in peripheral resistance
what neurotransmitter is released by the vagus nerve?
acetylcholine
what is the major cranial nerve in the parasympathetic nervous system?
vagus nerve
what impact will acetylcholine have on the heart?
slows heart rate and effect contractility mildly
does the parasympathetic nervous system innervate blood vessels?
no
explain how the parasympathetic nervous system impacts blood pressure if it does not innervate blood vessel.
autonomic centers in the brainstem increase the firing of parasympathetic neurons while inhibiting the firing of sympathetic neurons
what are the receptors that detect blood pressure?
baroreceptors
where are baroreceptors found?
- within the vessels
- common carotid artery and aortic artery
what hormone is a potent vasoconstrictor that increases blood pressure?
angiotensin II
what hormone is released by the heart and lowers blood pressure
atrial nutriuretic peptide (ANP)
which system is responsible for long-term maintenance of blood pressure?
urinary system
which hormones affect blood volume and how do they affect it?
- ANP: causes kidneys to excrete more water and sodium to decrease blood volume
- angiotensin-II: induces thirst, sodium retention, increases blood volume
- ADH: triggers thirst and increases water retained by kidneys to increase blood volume
- aldosterone: causes retention of sodium and water from the kidneys, increases blood volume
how do the kidneys influence blood pressure maintenance?
- blood pressure increases, more water flows through the kidneys than the cells can return to blood, water is then loss through urine
- blood pressure decreases, less water through the kidney and cells have more time to reclaim water and return it to the blood, decrease urine production and increase in blood volume and blood pressure
define perfusion
blood flow to a tissue through a capillary bed
how is perfusion different from blood flow?
it goes through a capillary bed
what is the name of the cells that form capillary walls?
pericytes
define capillary exchange
the movement of nutrients, gases, ions, and wastes between the blood in the capillary and the tissue cells
what are the three ways substances are exchanged?
- diffusion and osmosis through gaps and fenestrations
- diffusion through the membranes of endothelial cells
- transcytosis
what substances are exchanged in diffusion and osmosis through gaps and fenestrations?
water, monosaccharides, amino acids
what substances are exchanged in diffusion through the membranes of endothelial cells?
oxygen, carbon dioxide, certain lipids
