Week 3 - Circulatory System

Question 1

Define diffusion

Answer 1

The net movement of molecules from a region of high concentration to low. It happens bc of random collision

Question 2

How does temperature affect the rate of diffusion?

Answer 2

Hotter = faster

Question 3

Define bulk flow

Answer 3

Movement of a fluid from a region of high to low pressure. The pressure gradient is determined by an external force

Question 4

What is one advantage of super small animals [circ system]

Answer 4

Nearly every cell is in direct contact of external animal. So there is no need for a circulatory system. They rely on bulk flow to provide o2, eliminate waste

Question 5

What is the difference between open and closed circulatory systems?

Answer 5

Open: fluid = hemolymph. It flows through open-ended vessels. The hearts keep fluid in motion to constantly wash over organs.

Closed: fluid = blood. Blood completely enclosed in vessels

Question 6

Describe the travel of blood through arteries etc

Answer 6

Aorta, arteries, arterioles, capillaries, venules, veins, vena cava

Question 7

What is systolic pressure?

Answer 7

Pressure generated by the contracting heart.

~120 mmHg

Question 8

Name the pressure generated by the contracting heart

Answer 8

Systolic pressure

Question 9

Name the pressure generated by the relaxed heart/the recoiling of the arteries

Answer 9

Diastolic

Question 10

What is distolic pressure?

Answer 10

The pressure generated by the relaxed heart: the recoiling of the arteries

~80 mmHg

Question 11

What is peripheral resistance?

Answer 11

The friction experienced by blood as they come into direct contact with the walls of blood vessels

Question 12

Why are blood flow and pressure reduced in capillaries?

Answer 12

Peripheral resistance

Question 13

What is the Hagen-Poiseuille equation?

Answer 13

Q= (deltap pi r^4)/(8lm)

m= viscocity

Question 14

What is the no-slip condition?

Answer 14

Flow velocity of the fluid at the surface of the solid is NOT MOVING. maximum flow of the fluid is reached at some distance from the edge of the solid.

The place between max speed and no movement is called the gradient region

Question 15

What is edema?

Answer 15

Condition caused by protein deficiency. Causes an accumulation of fluid in interstitial space

Question 16

How does blood get back to the heart?

Answer 16

1. Smooth muscles contract, forcing blood to the next section and
2. one-way valves of veins prevent backflow.
3. Skeletal muscles apply more pressure

Question 17

What is the percentage of the body’s capillaries get blood st any given time? Why? What prevents blood from getting in capillaries?

Answer 17

5-10%

Blood pressure would flatline if all capillaries had blood all the time

Precapillary sphincters

Question 18

What are precapillary sphincters?

Answer 18

Prevent blood from entering most capillaries to maintain blood pressure

Question 19

How does the lymphatic system recapture fluid?

Answer 19

Fluid goes through lymphatic vessels to drain back into the subclavanian veins

Question 20

What causes blood clots when sitting in a plane for a while?

Answer 20

Lack of movement so lack of skeletal muscle contraction. Doesnt squeeze veins as much. Blood can pool and clot

Question 21

What separates atriums from ventricles?

Answer 21

Atrioventricular valves

Question 22

What are the junction connecting cardiocytes called?

Answer 22

Intercalated disks

Question 23

Name the two specialized cardiocyte clusters. What do they do?

Answer 23

1. Sinoatrial node
   Causes atria to contract in unison
2. Atrioventrical node
   Allow ventricles to contract

Question 24

What are the three stages of the cardiac cycle?

Answer 24

1. Atrial + ventrical systole stage (0.4 sec)
2. Atrial systole + ventricular diastole (0.1 sec)
3. Ventricular systole and atrial diastole (0.3 sec)

Question 25

How do you calculate cardiac output?

Answer 25

Cardiac output = heart rate (BPM) x stroke volume

Question 26

What is plasma

Answer 26

Liquid matrix that carries proteins, antibodies, electrolytes, nutrients, etc

Question 27

What is the percentage of plasma and cellular elements

Answer 27

plasma (55%), elements (45%)