Title: Physiology 2130 / Module 9: Circulatory System II

Q: The circulatory system is a [...] system.
A: closed

Q: [...] and [...]  transport blood away from the heart.
A: Arteries; arterioles

Q: [...] and [...] take blood back to the heart.
A: Venules; veins

Q: Gas exchange occurs within [...].
A: capillaries

Header: Label the type of blood vessel:

Q: Veins are aka capitance vessels because they contain [...] of the blood in the body.
A: most

Q: The body contains about [...]L of blood.
A: 5

Q: 2 smaller Circulatory Loops within the systemic loop are:
1. [...] (Digestive System);
2. [...] (Brain).
A: Hepatic Portal Loop; Hypothalamic-Hypophyseal Portal System

TBV in the following are:
Veins - 70%
Arteries - 10%
Heart and Lungs - 15%
Capillaries - 5%

Q: Blood [...], [...] and [...] depend on the type of blood vessel.
A: volume; pressure; velocity

Arteries have the highest blood pressure and velocity, but a low cross sectional area.
Arterioles have lower blood pressure and velocity, but a higher cross sectional area.
Capillaries have the lowest blood velocity but the highest cross sectional area.

Q: The blood pressure and the cross-sectional area [...] while velocity [...] in the veins and venules.
A: decrease; increases

Q: The [...] the pressure gradient, the [...] the blood flow.
A: higher; higher

Q: [...] the resistance, the [...] the flow.
A: Higher; lower
Extra: Flow = movement of blood through vessel, expressed as volume of blood/unit time.

Q: The [...] blood encounters is a result of the blood dragging along the walls of the vessels.
A: resistance

Q: Blood flow is [...] meaning the center moves in the center and slower as you get closer to the walls.
A: laminar (streamlined)
Extra: There are thin ‘layers’ or flow whose velocity varies across the vessel - flow is slower at the edges & faster in the center. Therefore, in order to examine blood flow through a vessel, we have to consider the pressure gradient & the resistance the fluid encounters.

Q: Factors that Effect Resistance:
1. [...] - thicker = higher resistance;
2. [...] - longer = higher resistance;
3. [...] - smaller vessel = larger resistance.
A: Thickness/viscosity of the fluid; Length of the vessel; Diameter or radius of the vessel
Extra: 1 & 2 are not major factors since viscosity of blood doesn't change and lengths do not change over a short period of time.
1 - Blood can get thicker through doping, or dehydration.
2 - Vessels can get longer in overweight individuals.
Makes the heart work harder in both cases.

Q: A [...] change in radius causes a [...] change in resistance.
A: small; very large
Extra: This is because of the formula for Blood Flow (Pressure Gradient x r^4), in which radius change is ^4.

Q: Ways to Alter Blood Flow:
1. Alter [...]; OR
2. Alter [...]
A: pressure gradient; radius

Q: If blood flow changes in a certain arteriole (ie. when feeding a certain organ), then the other arterioles will [...] their flow to compensate.
A: change

Q: How to Change Blood Flow to Organs to Meet Needs:
1. [...] - makes arterioles narrower
2. [...] - makes arterioles wider
A: Vasoconstriction; Vasodilation

Q: Blood produces [...] sounds when flow becomes turbulent due to systolic pressure.
A: Kortokoff's
Extra: When the sound disappears = due to diastolic pressure returned (laminar flow again).

Q: Pressure in the aorta ranges from [...]mmHg (systolic) and [...]mmHg (diastolic).
A: 120; 80

Q: 3 Layers of Arteries & Veins:
1. [...] - outermost layer made of fibourous connective tissue;
2. [...] - middle layer, made of smooth muscle and elastic tissue; &
3. [...] - innermost layer made of endothelial cells.
A: Tunica Externa; Tunica Media; Tunica Interna

Q: Veins have [...].
A: valves

Q: Capillaries are made of a single layer of [...] cells which permit for diffusion.
A: endothelial

Arteries Composition:
1. Have a lot of elastic tissue;
2. Dilate easily;
3. Low resistance; &
4. Little drop in blood pressure.

Q: Capillaries have [...] and [...] to allow the movement of water and most dissolved solutes.
A: clefts; fenestrations

Q: Oxygen is high in blood so will diffuse into [...] to be uptaken by tissues
CO2 is high in tissues to will diffuse into the [...].
A: insterstital fluid; blood

Q: [...] determine whether or not filtration or reabsorption occur.
A: Starling forces

Q: [...] = fluid moves from capillary to interstitial space.
[...] = fluid moves from interstitial space back into the capillary.
A: Filtration; Reabsorption

Q: Starling forces are [...] or [...].
A: hydostatic pressures; osmotic forces

Starling Forces:
Hydrostatic Pressures:
1. Capillary Hydrostatic Pressure
2. Interstitial Fluid Hydrostatic Pressure
Osmotic:
3. Osmotic Force of Plasma Proteins
4. Osmotic Force of Proteins in Intersitial Space

Q: The [...] is a large network of capillaries and vessels that returns the excess fluid to the systemic circulation.
A: lymphatic system

Q: Lymph capillaries are [...] and pass the fluid to a larger collecting vessel that pass through the lymph nodes and filter it before sending it back to [...].
A: blind-ended; venous circulation

Q: The accumulation of fluid in the interstital space causing swelling is called [...].
A: edema

Q: Factors that Produce Edema:
1. Increase in [...] caused by increased blood pressure - can be caused by weight lifting.
2. Decrease in [...] - occurs in cases of severe malnutrition.
3. Blockge or disruption of [...] - if any nodes are removed.
A: capillary hydrostatic pressure; plasma osmotic force; lymphatic system

Q: Regulation of Blood Flow (the Cardiovascular System):
1. [...] in the organs themselves.
2. [...] that rely on chemicals in the blood.
3. [...] which alters cardiac output and blood flow to organs.
A: Local Control Mechanisms; Humoral Mechanisms; Autonomic Nervous System

Q: [...] is the ability of most tissues to control their own blood flow.
A: Autoregulation

Q: Local control mechanisms have 2 theories:
1. [...] posits that changes in blood flow are produced by a contraction or relaxation of the smooth muscle in the walls of blood vessels.
2. [...] posits that changes in blood flow (vasodilation) occurs during exercise (ie.the working muscle heats up, uses oxygen, & produces carbon dioxide, lactic acid, & adenosin (from the breakdown of ATP).
A: Myogenic Theory; Metabolic Theory
Extra: These metabolic by-products act locally on the blood vessels, causing a local vasodilation & increased blood flow in the arterioles leading the muscle, that is, the alter the active tissue. Once the exercise stops & these metabolites are washed out, the vessel will return to its original size & blood flow decreases to normal.

Q: Humoral regulators are either [...] or [...].
A: vasoconstrictors; vasodilators

Vasoconstricting Agents include:
1. Epinepherine is released from the adrenal gland in response to a fight or flight situation.
2. Angiotensin II is one of the most powerful vasoconstrictors in the body; it's important in the renal system.
3. Vasopressin (aka antidiuretic hormone or ADH) is important in the renal system.

Vasodilating Agents Include:
1. Epinephrine is released during fight or flight situations; causes vasodialtion in skeletal and cardiac muscle in fight or flight.
2. Kinins are found in plasma and tissues.
3. Histamines are released from cells after they have been damaged.
4. Atrial Natriuretic Factor (ANF) is produced by atrial muscle cells.

Q: The sympathetic nervous system causes overall [...], but also produces [...] in blood vessels in working muscles.
The parasympathetic nervous system causes [...].
A: vasoconstriction; vasodilation; vasodilation

Q: The cardiovascular system uses the [...] to regulate blood pressure.
A: Baroreceptor reflex

Q: [...] is the average pressure in the arterial side of the circulation.
A: Mean Arterial Pressure

Q: [...] is the sum of all the resistance in all the blood vessels in the body throughout the circulatory system.
A: Total Peripheral Resistance