& Verified Answers
about 75 bpm Correct answer-average heart rate
about 100 bpm Correct answer-what would heart rate be without nervous system control?
interneurons in "brain centres" Correct answer-what initiates visceral motor responses?
centre Correct answer-a collection of interneurons that receive sensory input and create a motor
output to alter it
- cardioaccelerator neurons
- cardioinhibitory neurons
- vasomotor control (vessels) Correct answer-regulates blood pressure and function
increase HR and BP
- sympathetic
- visceral motor neurons
- norepinephrine (NE)
- increased AP at SA node Correct answer-cardioaccelerator centre
230 bpm Correct answer-what is the maximum heart rate that SA node excitation can handle?
decrease HR and BP
- parasympathetic
- visceral motor neurons
- acetylcholine (Ache)
- decreased AP at SA node Correct answer-cardioinhibitory centre
Intracellular fluid Correct answer-fluid in cells
proprioceptors Correct answer-sensory input from muscles and tendons
- physical activity
baroreceptors Correct answer-sensory input from vessels
- vessel pressure
chemoreceptors Correct answer-sensory input from vessels
- CO2 and O2 levels
arteries Correct answer-carry blood away from the heart
veins Correct answer-carry blood to the heart
capillaries Correct answer-thinnest vessels that do gas/nutrient exchanges
veins and venules
- about 60% Correct answer-where is the largest volume of blood in the body?
, tunica intima
- endothelium and connective tissue Correct answer-innermost layer of blood vessel wall (A)
tunica media
- smooth muscle
- controls vasomotion Correct answer-middle layer of vessels (C)
vasoconstriction
- NE from adrenal gland Correct answer-contraction of tunica media
vasodilation
- Ache Correct answer-relaxation of tunica media
tunica externa
- mostly collagen
- vasa vasorum Correct answer-outermost layer of vessels (E)
elastic artery
- most elastin
- low resistance vessel (continuous flow) Correct answer-thick-walled vessels found close to heart
muscular arteries
- thick tunica media
- vasoconstrictor Correct answer-vessels that deliver blood to specific organs
arterioles
- lots of resistance
- vasomotion Correct answer-smallest artery; feeds into capillary bed
aneurysm
- can be hereditary or acquired Correct answer-balloon like bulge in wall of blood vessels due to
weakened arterial walls
scurvy
- weakened blood vessels
- swollen gums
- teeth loss Correct answer-lack of vitamin C disrupts collagen production
capillaries
- only tunica intima Correct answer-vessels that connect arterioles and venules
sphincter muscle Correct answer-control blood flow through capillary beds
continuous capillaries
- skin, muscle, lungs, CNS Correct answer-most common capillaries; least permeable; tightly joined
endothelial cells; intercellular clefts allow passage of small molecules
fenestrated capillaries
- kidneys and small intestines (filtration and hormones) Correct answer-capillaries that have pores
the allow more permeability; passage of larger molecules