Blood Vessels and Blood Pressure Chapter 10 Pt. 2

Local heat causes vasodilation and local cold causes vasoconstriction
Stretch response increases tone
Decrease in pressure decreases tone

Neuronal and Hormonal

Cardiovascular control center regulates sympathetic nervous system.
The CCC has sympathetic nerve endings that release norepinephrine and cause vasoconstrictions. (Alpha 1 adrenergic receptors).

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.

Vasopressin(ADH) and angiotensin 2 are vasoconstrictors
Vasopressin controls water balance in kidneys
Angiotesin 2 controls salt balance in kidneys

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.

Leaky, Large

The capillaries are a lazy river for blood as nutrients and material need to be exchanged. Increased surface area will slow down the velocity.

Veins

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.

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.

Venous system

Blood volume reservoir
Returns blood back to heart
Large internal radi and low resistance
Contains 60% of body blood volume at rest

Volume of blood entering each atrium per minute, has the lowest pressure

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

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

MAP is the main driving force propelling blood
Cardiac output, total peripheral resistance (TPR), and blood volume determine bp

Cardiac output and total peripheral resistance

Receptors that monitor MAP and generate AP through afferent pathways of cardiovascular control center (CCC).
Efferent pathways includes autonomic nervous system.

Blood volume
Osmoreceptors located in left atria and hypothalamus
regulates plasma volume
vasopressin and angiotensin II