term 4 week 1 pressure gradients and then some

Question 1

Pulse

Answer 1

• Result of the alternating expansion and contraction of the arteries
• Can be palpated at certain places on the body where the arteries are close to the surface

Question 2

Pulse pressure (PP)

Answer 2

• The difference between SBP and DBP
• PP = SBP - DBP
• It is a calculated figure not a physical event

Question 3

Mean Arterial Pressure (MAP)

Answer 3

• The driving pressure in the arterial system that keeps blood flowing
• A weighted average of systemic blood pressure to account for the heart spending more time in diastole
• NOT the arithmetic average of SBP and DBP
• MAP = DBP + 1/3 (SBP - DBP)

Question 4

Changes in MAP occur due to:

Mean arterial pressure = MAP

Answer 4

• Abnormal increases in blood volume
  Increased salt intake
• Abnormal decreases in blood volume
  Dehydration
  Hemorrhage

Question 5

Abnormal decreases in blood volume

Answer 5

Dehydration
Hemorrhage

Question 6

Abnormal increases in blood volume

Answer 6

increased salt intake

Question 7

Any factor that alters blood volume will affect ___

Answer 7

BP

Question 8

The volume of the blood in the arteries is directly proportional to __

Answer 8

BP

Question 9

A hemorrhage causing a loss in blood volume will cause a _______ in BP

Answer 9

decrease

Question 10

The restoration of BP, such as during a blood transfusion, will increase the volume of blood thereby ______ BP

Answer 10

increasing

Question 11

Peripheral Resistance

Answer 11

• The force that opposes blood flow
• Caused by friction between the blood and the walls of the blood vessel

In order for blood to flow, BP must be greater than the peripheral resistance
* BP decreases as the distance from the left ventricle increases

Question 12

In order for blood to flow, BP must be greater than the _________

Answer 12

peripheral resistance

Question 13

BP decreases as the distance from the left ventricle _______

Answer 13

increases

Question 14

Sources of peripheral resistance

Answer 14

• Blood viscosity
• Refers to the thickness of the blood
• Vessel length
• Vessel radius

Question 15

Blood Viscosity

Answer 15

• Related to the density of blood cells in the plasma
• Direct relationship between blood viscosity and peripheral resistance
• ↑ viscosity = ↑ peripheral resistance; ↓ viscosity = ↓ peripheral resistance
• Inverse relationship between blood viscosity and blood flow (impedes
  blood flow)
• ↑ viscosity = ↓ blood flow; ↓ viscosity = ↑ blood flow
• Any condition that increases or decreases the concentration of blood
  cells or plasma proteins may alter blood viscosity
• Anemia or hemorrhage = ↓ blood viscosity
• High altitude or dehydration = ↑ blood viscosity

Question 16

Direct relationship between blood viscosity and peripheral resistance

increase viscosity = _______ PR

decrease viscosity = ________ PR

Answer 16

↑ viscosity = ↑ peripheral resistance

↓ viscosity = ↓ peripheral resistance

Question 17

Inverse relationship between blood viscosity and blood flow (impedes
blood flow)

increase viscosity = _______ PR

Decrease viscosity = _______ PR

Answer 17

↑ viscosity = ↓ blood flow

↓ viscosity = ↑ blood flow

Question 18

Any condition that increases or decreases the concentration of blood
cells or plasma proteins may alter blood _______

Answer 18

viscosity

Blood viscosity, also known as blood thickness or resistance to flow

Question 19

Anemia or hemorrhage = __ blood viscosity
High altitude or dehydration = __ blood viscosity

Answer 19

Anemia or hemorrhage = ↓ blood viscosity

High altitude or dehydration = ↑ blood viscosity

Question 20

Anemia or hemorrhage will have what affect on viscosity ?

Answer 20

decreases blood viscosity

Question 21

High altitude or dehydration will have what affect on viscosity ?

Answer 21

increases blood viscosity

Question 22

Direct relationship between vessel length and ________ to blood flow

Answer 22

resistance

• The greatest effect of vessel length on peripheral resistance is found in the
  blood vessels of the systemic circuit
• Blood vessels in the pulmonary circuit are shorter (and more elastic)
• Therefore, resistance to blood flow in the pulmonary circuit is lower in comparison to the systemic circuit

Question 23

Vessel diameter is associated with the amount of ______ between the blood
and the walls of blood vessel

Answer 23

friction

• Blood flowing close to the wall of the blood vessel is slowed due to friction
• Blood flowing down the center of a blood vessel meets less friction, therefore blood flows faster
• Large-diameter vessels offer less resistance to blood flow
• More blood is able to flow down the center of the blood vessel
• Small-diameter vessels offer greater resistance to blood flow
• More blood is in contact with the wall of the blood vessel

Question 24

Central Venous Pressure

Answer 24

• Corresponds with the pressure in the right atrium
• Central venous pressure is measured in the right atrium because all of the veins in the systemic circuit empty into this heart chamber
• Blood pressure decreases as it flows out of the arterial circulation and into the venous circulation

Question 25

Venous blood flow is maintained via

Answer 25

Respiratory pump * Depends on pressure changes in the ventral body cavity associated with breathing * It helps to move blood upward toward the heart Muscle pump * Skeletal muscle contractions function to “milk blood” back to heart

Question 26

Movement of Fluid Across Capillary Walls * To exchange nutrients, gases, and metabolic byproducts between blood and cells * This is ______ in arteries and veins because the vessel walls are too thick to allow rapid diffusion * To maintain normal distribution of the extracellular fluid

Answer 26

impossible

Question 27

Capillary exchange is made possible by three forces at work simultaneously

Answer 27

* Diffusion * Filtration * Osmosis

Question 28

Diffusion

Answer 28

* Accounts for the exchange of oxygen and most nutrients such as amino acids, fatty acids, and glucose, carbon dioxide, hormones, etc. * Occurs along the entire length of the capillary bed * Solutes move down their concentration gradient from areas of higher concentration to areas of lower concentration. * For example, oxygen and nutrients diffuse from the blood into cells * Conversely, carbon dioxide and metabolic waste products diffuse from the cells into the blood * The direction and magnitude of water movement across capillary walls depends on the balance between hydrostatic pressures and osmotic pressures

Question 29

Filtration

Answer 29

The movement of fluids through a capillary wall is due to hydrostatic pressure * The force exerted by a fluid pushing against a wall * In capillaries, hydrostatic pressure is the capillary BP * Capillary BP is influenced by: * Arterial pressures * Venous pressures * Resistance in the pre- and post-capillary sphincters * Filtration occurs primarily at the arterial end of the capillary where hydrostatic pressure is high, and decreases along the length of the capillary as hydrostatic pressure decreases * Filtration is a passive process accounting for movement of solutes such as ions

Question 30

Osmosis

Answer 30

* Water movement from an area of lower solute concentration to an area of higher solute concentration * Occurs in response to oncotic pressure * Osmotic pressure exerted by proteins * Plasma proteins (mainly albumin) are large, lipid insoluble particles that do not leave the blood in capillaries * Osmotic pressure in capillaries does not change along the length of vessels * Plasma proteins remain in the capillaries, exerting a fixed amount of osmotic pressure along its entire length * Plasma proteins create an osmotic pressure greater than the osmotic pressure of the interstitial fluid * Therefore, blood in the capillary has a greater attraction for water than does interstitial fluid

Question 31

Starling Forces * Forces driving fluid into and out of the __________ * These forces are balanced and counteracted by high capillary hydrostatic pressure and osmotic pressures

Answer 31

capillaries

Question 32

Forces that promote filtration and drive fluids out of the capillary:

Answer 32

* Capillary hydrostatic pressure * Interstitial fluid osmotic pressure

Question 33

Forces that promote fluid absorption and pull fluids into the capillary:

Answer 33

* Capillary osmotic pressure * Interstitial fluid hydrostatic pressure

Question 34

net movement of starling forces

Answer 34

* Usually more fluid leaves the capillary at the arterial end than returns at the venous end * Excess fluid is collected by the lymphatic system and returned to the systemic circulation.

Question 35

The Lymphatic System * Maintain ________ balance * Drains tissue spaces of excess ______ fluid * Defend body against disease (immunity) * Produces and maintains _______ * Transport dietary fats (digestion) * Carries lipids (and lipid soluble vitamins) from their site of absorption in the GI tract to the blood

Answer 35

fluid interstitial lymphocytes

Question 36

Formation of Lymph * About __ L of excess fluid is formed per day * More fluid is filtered out of the capillaries than is reabsorbed by the capillaries * This fluid drains into the lymph capillaries and becomes lymph fluid * Interstitial fluid has essentially the same composition as plasma, but the interstitial fluid has a much lower concentration of plasma proteins

Answer 36

3 L

Question 37

Lymph Function * Return _______ _______ to blood circulation * Excess plasma proteins in interstitial spaces would exert osmotic pressure causing a decrease in fluid absorption at the venous end of capillaries * Tissue edema or swelling would occur * As excess interstitial fluid accumulates it pushes against the outside of lymph capillaries, opening the flaps in the lymph capillary walls allowing fluid to enter * Once inside, the fluid pushes the flaps in the lymph capillary wall closed, preventing lymph from flowing back into the interstitial space

Answer 37

plasma proteins

Question 38

lymph dependent on outside forces to move the lymph what are they?

Answer 38

Respiratory pump * Pressure changes in the ventral body cavity associated with breathing * Increased intra-abdominal pressure squeezes the abdominal lymph vessels and moves the lymph toward the heart Muscle pump * Skeletal muscle contractions function to “milk lymph” back to heart * Lymphatic valves prevent the backflow lymph in the system (just like venous flow)