Physiology

Question 1

What are the steps of blood moving throughout the heart?

Answer 1

1. Deoxygenated blood enters the right atrium through the venae cavae, and moves through to the right ventricle
2. Blood exits the heart through the pulmonary artery, where it then travels to the lungs to be oxygenated
3. The now oxygenated blood enters the heart again through the pulmonary vein into the left atrium, and moves into the left ventricle
4. This blood then exits the heart via the aorta and travels to all of the body’s tissues to supply them with O2

Question 2

What are the two different types of circulatory systems and define them?

Answer 2

Pulmonary and Systemic circuits.

Pulmonary= the system which moves blood between the heart and the lungs to be oxygenated

Systemic= the system which moves blood between the heart and the rest of the body

Question 3

What occurs when the aorta receives blood?

Answer 3

When the aorta receives blood there is an increase in pressure causing the vessel to increase in volume, it then retracts when the pressure drops, pushing blood forward.

Question 4

What is cardiac output?

Answer 4

The volume of blood put out by the heart

- the blood vessels act as a hydraulic filter converting pulsatile flow to steady

Question 5

How do arterioles react when blood flows from the heart?

Answer 5

arteries and arterioles have elastic walls so they distend when blood is ejected from the heart and recoil during diastole

Question 6

Is blood flow slower in arteries or capillaries?

Answer 6

capillaries to ensure adequate diffusion

Question 7

Where does a pulse pressure originate from?

Answer 7

• it is the difference between diastolic and systolic blood flow
  The radial stretch of the aorta initiates a pressure wave which is later detected as a pulse

Question 8

What does the velocity of flow depend on?

Answer 8

The cross sectional area of a tube

Question 9

What occurs in Ischaemic Heart Attacks (TIA)?

Answer 9

A person with a constricted subclavian artery may experience a temporary lack of blood flow to the brain

• Blood speeds up to get past a constriction in the vessel, as velocity increases, pressure decreases, causing the blood to flow back down the artery

Question 10

Where is most of the fluid in the human body?

Answer 10

• the greatest proportion of fluid is in intracellular fluid, otherwise it exists in plasma and interstitual fluid (extracellular)

Question 11

How is the bulk movement of water facilitated?

Answer 11

• Through aquaporins

Question 12

What is the difference between a semi permeable and a selectively permeable membrane?

Answer 12

semi- is permeable only to water, ideally

selectively- is permeable to some substances and not to others

Question 13

What is diffusion vs osmosis?

Answer 13

Diffusion= in diffusion both solute and solvent move until solute equilibrium is reached

Osmosis= in osmosis only the solvent moves until equilibrium is reached

Question 14

What does “osmolarity of a solution” refer to?

Answer 14

the total concentration of all solute particles

Question 15

What does tonicity refer to?

Answer 15

the total concentration of just non penetrating solute particles

Question 16

Where does water flow in osmosis?

Answer 16

Always from an area of low solute concentration to an area of high solute concentration

Question 17

Describe the difference between

• hypotonic
• hypertonic
• isotonic

Answer 17

hypotonic= the concentration of non penetrating solutes is higher in the cell

hypertonic= the concentration of non penetrating solutes is higher out of the cell

Isotonic= the concentration of non penetrating solutes is equal in and outside of the cell

Question 18

Are osmolarity and tonicity the same?

Answer 18

NO

Question 19

How does Aveolar Sac structure work?

Answer 19

The lungs contain 600 million alveoli

• The Alveolar membrane between air and blood is extremely thin
• Therefore oxygen molecules diffuse across the membrane rapidly
• The oxygen concentration leaving the lungs is almost equal to the concentration in the alveolus