1Intrinsic physical controls that can change tonicity of vessels?
Local heat causes vasodilation and local cold causes vasoconstriction
Stretch response increases tone
Decrease in pressure decreases tone
2What are the 2 kinds of extrinsic controls?
Neuronal and Hormonal
3What is neuronal extrinsic control?
Cardiovascular control center regulates sympathetic nervous system.
The CCC has sympathetic nerve endings that release norepinephrine and cause vasoconstrictions. (Alpha 1 adrenergic receptors).
4What is hormonal extrinsic control?
Adrenal medulla is stimulated by sns to release epinephrine and NE to reinforce its action.
Epinephrine combines with alpha 1 and beta 2 receptors
Norepinephrine combines with alpha 1 receptors
Beta 2 receptors lead to vasodilation, particulary in skeletal and cardiac muscle.
5What leads to Vasoconstrictions in hormonal extrinsic control?
Vasopressin(ADH) and angiotensin 2 are vasoconstrictors
Vasopressin controls water balance in kidneys
Angiotesin 2 controls salt balance in kidneys
6How do you enhance rate of diffusion of material in capillaries?
Fick's Law:
- Concentration gradient will enhance
- Permeability will enhance
- Surface area will enhance
- Distance and size will decrease the rate of diffusion
Capillaries have thin walls, travel a short distance, and display extensive branching.
7Continuous capillaries have _____ junctions while, fenestrated capillaries have _____ pores.
Leaky, Large
8How does blood velocity impact the diffusion rate of the capillaries?
The capillaries are a lazy river for blood as nutrients and material need to be exchanged. Increased surface area will slow down the velocity.
9Where is the lowest blood pressure located?
Veins
10How is movement regulated by the capillaries?
Metarteriole run between arterioles and venules.
Precapillary sphincters surround the metarterioles.
The precapillary sphincters are a ring of smooth muscle (myogenic control) that regulate tone.
11Function of Lymphatic system?
Returns excess filtered fluid, proteins and lipids to body.
Immune lymph nodes filter pathogens.
Lymph is interstitial fluid that is pushed into the lymphatic vessel.
12Where does lymph from lymphatic system drain to?
Venous system
13Function of veins
Blood volume reservoir
Returns blood back to heart
Large internal radi and low resistance
Contains 60% of body blood volume at rest
14Define Venous return?
Volume of blood entering each atrium per minute, has the lowest pressure
15What is Intrinsic Regulation of venous return?
As venous capacity increases, the blood returning to the heart decreases.
bulk flow and long-term water-regulating mechanisms are intrinsic regulating factors that control blood volume
16What are extrinsic factors that enhance venous return?
Sympathetic stimulation of smooth muscle in veins
Vasoconstriction that increases pressure gradient
Valves
Skeletal muscle activity will compress the veins
Respiratory pump and cardiac suction
17How is blood pressure regulated?
MAP is the main driving force propelling blood
Cardiac output, total peripheral resistance (TPR), and blood volume determine bp
18What does short term blood pressure regulation include?
Cardiac output and total peripheral resistance
19What are Baroreceptors?
Receptors that monitor MAP and generate AP through afferent pathways of cardiovascular control center (CCC).
Efferent pathways includes autonomic nervous system.
20What does long term blood pressure regulation include?
Blood volume
Osmoreceptors located in left atria and hypothalamus
regulates plasma volume
vasopressin and angiotensin II