Circulation Flashcards
Medium sized arteries, contain smooth muscle fibers, distribution to organs.
Muscular arteries
Small almost microscopic, artery that delivers blood to capillaries, smooth muscle helps regulate blood pressure.
Arteriole
Microscopic vessels that connect are fooled to venules, permit exchange of nutrients and waste between the body’s cells and the blood.
Capillaries
Carry blood back to the heart.
Veins
Rings of smooth muscle at the point where capillaries branch from aterioles.
Pre-capillary sphincters
Movement of substances in and out of capillaries.
Capillary exchange
Pulls fluid into capillaries
Blood colloid osmotic pressure.
Several capillaries untie, receive blood from capillaries and empty into veins.
Venules
Thin weakened section of the wall of an artery or vein that bulges outward forming balloon like sac.
Aneurysm
The volume of blood flowing back to the heart through systemic veins.
Venous return
Venous return two mechanisms
Blood enters veins at very low pressure and skeletal muscle contractions.
Opposition to blood flow due to restriction between blood and walls of blood vessels.
Vascular resistance
Blood flow through vessels
From high pressure area to lower pressure area, that is down pressure gradient.
Factors that regulate blood flow and blood pressure?
Blood volume and ventricular contraction and vascular resistance.
Cardiovascular center location
In the medulla
Cardiovascular center functions
Regulate heart rate, stroke volume ,blood pressure and blood flow to tissues.
Cardiovascular center mechanisms
Neural mechanisms and hormonal mechanisms.
Input to cardiovascular center function
To inform brain that BP should be altered.
Input from cardiovascular center parts of the brain.
Cerebral cortex- thoughts decisions
Limbic system- emotions
Hypothalamus- changes in temp or blood volume
Monitor movements of joints and muscles, provide input to cardiovascular center during physical activity.
Proprioceptors
Located in aorta, internal carotid arteries, send impulses continuously to cardiovascular center to help regulate blood pressure?
Baroreceptors
Located in choroid bodies and aorta, monitor blood levels of O2, CO2 and H+
Chemoreceptors
Sends impulses to arterioles throughout body, result in moderate state of vasoconstriction called
Vasomotor tone
When blood pressure falls
Produce hormone angiotensin II which raises blood pressure by causing vasoconstriction.
Renin-angiotensin- aldosterone system
In response to sympathetic stimulation, the adrenal, these hormones increase cardiac output by increasing the rate and force of heart contractions.
Epinephrine and norepinephrine
Causes vasoconstriction which increases blood pressure for this reason ADH is also called?
Vasopressin
Lowers blood pressure by causing vasodilation and promoting the loss of salt and water in the urine, which reduces blood volume
Atrial natriuetic peptide (ANP)
Alternate expansion and elastic recoil of an artery after each contraction and relaxation of the left ventricle
Pulse
Pulse sites
Radical artery ( thumb side of wrist) Carotid artery ( neck) Brachial artery (arm)
Rapid resting heart rate > 100 bpm
Tachycardia
Slow resting heart rate below 50 bpm
Bradycardia
Device used to measure blood pressure?
Shygmomanometer
Includes arteries and arterioles that carry blood containing oxygen and nutrients from left ventricle to systemic capillaries throughout the body.
Systemic circulation
Carries blood from right side of heart to lungs to get O2 and eliminate CO2
Pulmonary circulation
Vein that carries blood between one capillary network and another is called?
Portal veins
Leaky capillaries in liver
Sinusoids
Circulatory system of a fetus
Fetal circulation
Volume blood from systemic veins and venules ?
64%
Volume of blood in systemic arteries and arterioles
13%
Blood volume in systemic capillaries
7%
Blood volume in heart chambers
7%
