heart

Question 1

DIFFERENCES IN FISH AND MAMMAL HEARTS

Answer 1

fish - single loop circulatory system where blood passes through the heart once per circuit/two-chambered - blood is oxygenated through the gills before being pumped to the rest of the body
mammals - double-loop circulatory system where blood passes through the heart TWICE per circuit/four-chambered - separation of oxygenated and deoxygenated blood, leading to efficient transport of oxygen to tissues

Question 2

Skeletal vs cardiac muscles (5 pts.)

Question 3

cardiac muscles are myogenic

Question 4

Arteries

Answer 4

moving blood AWAY from the heart

Question 5

Aorta

Answer 5

Carries oxygenated blood to the body from the left ventricle
Very thick, elastic muscle wall; can withstand very high pressure

Question 6

Pulmonary artery

Answer 6

Four branches carry deoxygenated blood from the right ventricle to the right and left lungs
Thick, elastic muscle wall to withstand and maintain high pressure (although not as much as is generated in the aorta)

Question 7

Coronary arteries

Answer 7

Arteries visible on the external surface of the heart
Carry the freshest, oxygenated and nutrient rich blood from the aorta to the heart muscle itself

Question 8

Veins

Answer 8

Moving blood TOWARDS the heart

Question 9

Superior vena cava and Inferior vena cava

Answer 9

Superior vena cava
- Brings deoxygenated blood from the head and upper body to the right atrium
- Large diameter, thin muscle wall, little pressure.

Inferior vena cava
- Brings deoxygenated blood from the lower body to the right atrium
- Large diameter, thin muscle wall, little pressure

Question 10

Pulmonary vein

Answer 10

Bring oxygenated blood from the right and left lungs to the left atrium
Thin-walled, low pressure.

Question 11

Cardiac veins

Answer 11

Veins visible on the external surface of the heart
Carry deoxygenated blood from the capillaries in the heart back to the right atrium
Remove wastes from the heart muscle

Question 12

Pocket Valves

Answer 12

found in the blood vessels
leaving the heart:
- aortic & pulmonary semilunar valve (both have 3 semilunar cusps)

Question 13

OTHER 2 TYPES OF valves:

Answer 13

tricuspid valve (blocks backflow from the right ventricle into the right atrium) & bicuspid valve (prevents backflow from the left ventricle into the left atrium)

Question 14

WHY DO WE HAVE VALVES?

Answer 14

Valves prevent backflow of blood and keep the blood moving in one direction through the heart.

Question 15

The transport system

Answer 15

nutrients, oxygen, heat, and hormones through a network of arteries, veins, and capillaries.

Question 16

Components of Blood

Answer 16

Plasma - dissolves or carries all other components of blood, nutrients, wastes, etc.

Erythrocytes - transport oxygen

Leucocytes: phagocytes - eat up pathogens and dead cells / lymphocytes - for the immune response (create antibodies)

Platelets - clotting of blood following damage to cells

Question 17

BLOOD VESSELS

Answer 17

Arteries carry high pressure blood away from the heart to tissues that need it (> than 10μm)

Capillaries are very small (around 10 μm diameter) and therefore can penetrate virtually every tissue in the body. Blood moves slowly through them under low pressure providing opportunities for the exchange of substances.

Veins carry the low pressure blood back to the heart using valves to ensure blood flows in the correct direction(variable but much larger than 10μm)

n.b. arteries and veins tend to be large structures, smaller arteries are known as arterioles and correspondingly smaller veins are venules.

Question 18

STRUCTURE OF ARTERIES

Answer 18

• THICK MUSCULAR WALL AND FIBROUS OUTERLAYER HELPS WITHSTAND HIGH BLOOD PRESSURE
• SMALL LUMEN MAINTAINS HIGH BLOOD PRESSURE (LUMEN DECREASES WHEN MUSCLE CONTRACTS; INCREASES WHEN ELASTIC FIBRES STRETCH WITH EACH PULSE OF BLOOD)

Question 19

STRUCTURE OF CAPILLARIES

Answer 19

• ALLOWS FOR EXCHANGE OF SUBSTANCES TO AND FROM THE BLOOD
• ALLOWS FOR TISSUES TO GAIN NUTRIENTS AND GET RID OF WASTE
• ALLOWS SUBSTANCES TO LEAVE ORGANISM; E.G., GASS EXCHANGE IN THE LUNGS W/ OXYGEN AND CO2
• wall is one cell thick, allows for easy diffusion because of short diffusion distance
• basement membrane is permeable
• wall & basement membrane can also have pores to quicken the rate of diffusion
• very small lumen, big SA, allows for the exchange of a lot of substances!

Question 20

veins

Answer 20

Veins return blood to the heart for re-circulation. The flow is irregular.
The large lumen (compared to arteries and the thickness of the wall) means that the blood is under low pressure.
Because there is less pressure to resist the walls of the veins are thinner and less elastic than arteries. They also contain less muscle than the arteries.

Veins typically pass between skeletal muscle groups, which facilitate venous blood flow via periodic skeletal contractions.
Veins typically run parallel to arteries, and a similar effect can be caused by the rhythmic arterial bulge created by a pulse.

HAS VALVES

Question 21

KNOW T- CHART