Cardiovascular and Circulatory System Pt.3 Flashcards
Blood vessels carry blood throughtout the body there are 5 types _________
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
Arteries do what ____________
Carry blood away from heart
Arterioles connect ________
Arteries and capillaries
Capillaries allow ____________
Exchange between blood and cells
Venules connect __________
Capillaries and veins
Veins do what __________
Carry blood to the heart
Blood vessels vary in _______ and ________
Diameter and composition
What do all blood vessels have?
Lumen and endothelium
Lumen is ___________
The space inside of the blood vessel
Endothelium is __________
The inner lining
Some blood vessels contain __________, which maintains _____________
- Contain smooth muscle
- Maintains partial contraction (muscle tone)
Vasoconstriction _________________
Decreases size of vessel lumen
Vasodilation _______________
Increases size of vessel lumen
What do arteries act as?
Pressure reservoir
Arteries maintain blood flow during __________
Ventricular relaxation
Arterioles are sites of __________
Variable resistance
Arterioles direct distribution of blood flow to ________
Individual tissues via hormones, autonomic nervous system etc
What are arterioles regulated by?
- Paracrine signals
- Autonomic nervous system neurotransmitters
- Hormones
What is an example of paracrine signals (arterioles)?
O2 leads to vasodilation due to secretions by vascular endothelium or local cells (active hyperemia)
What is an example of autonomic nervous system neurotransmitters (arterioles)?
Norepinephrine released by neurons of sympathetic nervous system
What is an example of hormones (arterioles)?
Epinephrine released from adrenal medulla
Arterioles regulation allows for ________
Blood to be pushed to where it’s needed
Capillaries have a ________ to facilitate ________
-Very thin wall (single cell layer)
-Exchange of materials
Capillaries facilitate movement of __________
Water, O2, CO2, and glucose
Most cells are located within _____mm of the nearest capillary
0.1 mm
Pericytes are _________
Contractile cells associated with capillaries
Pericytes regulate the _________ of capillarity permeability (more pericytes= less leaky)
“Tightness”
Capillaries vary in permeability __________
Throughout the body
Continuous capillaries (most common) have ______
Endothelial cells joined with leaky junctions
Fenestrated capillaries have ________ for _____
-Large pores
-For larger volumes of fluid to pass between plasma and interstitial fluid
Substances pass through capillaries via _______ or ______
-Diffusion (passive transport for dissolved solutes like O2)
-Transcytosis (active transport for larger molecules)
Fluid moves into/out of capillaries as a result of ____
Hydrostatic or osmotic pressure gradients
Filtration is ___________ and is driven by _______
-Fluid movement out of capillaries
-Hydrostatic pressure (blood pressure)
Absorption is _______ and is driven by ______
-Fluid movement into capillaries
-Oncotic pressure (pulling pressure from plasma proteins)
Due to the pressure differences in arterial vs venous end of capillaries ________ and _________
-Net filtration at arterial end
-Net absorption at venous end
Venules transport ______________
Blood from capillaries to veins
Veins transport ___________ and act as _______
-Blood toward the heart
-Volume reservoir
-Hold majority of blood
Compared to arteries, veins ___________
- Are more numerous and closer to skin
- Have thin wall with less elastic tissue (expand easily)
- Have larger diameter and lumen
Venous return is
The return of blood to the right side of the heart
Venous pressure is ___ and the large lumen ______
-Low
-Offers little resistance, so active mechanism are needed
Lymphatic system allows for
One-way movement of interstitial fluid into the circulatory system
Lymphatic system does what
- Returns fluid and proteins to circulatory system
- Pick up absorbed fat and transfer it to circulatory system
- Serve as filter for pathogens
Tiny lymph capillaries lie close to _________
Blood capillaries
Lymphatic vessels progressively increase ______ and empty into venous circulation via subclavian vein
In size
Lymph nodes (tissue nodules containing lymphocytes/macrophages) __________
Monitor fluid
Lymph flow occurs by ___________
Mechanisms similar to venous return
Edema (swelling) is
An accumulation of fluid in the interstitial space
Blood pressure is highest in ______ and lowest in ______ (as energy is lost due to resistance to flow)
-Arteries
-Veins
Systolic pressure (av 120mm Hg) is during ________
Ventricular systole
Diastolic pressure (av 80mm Hg) is during ________
Ventricular diastole
Pulse is felt
as pressure waves are transmitted into fluid-filled arteries (disappears in capillaries, where blood has continuous movement)
A sphygmomanometer and stethoscope are used __________
To measure arterial blood pressure
Arterial pressure is pulsatile, so mean arterial pressure (MAP) represents _____________
Driving pressure of blood flow
What is the formula of MAP?
MAP= diastolic pressure + 1/3 (systolic pressure-diastolic pressure)
Mean arterial pressure (MAP) is homeostatically controlled by the ____________
Baroreceptor reflex
