Topic 4- Blood Vessels And Lymph

Question 1

Structure of arteries:

Answer 1

• outer layer of fibrous tissue
• thick middle layer of elastic and muscle tissue
• inner endothelium layer
  Small lumen

Question 2

Structure of arterioles:

Answer 2

Thinner than arteries

Middle layer of smooth muscle tissue for vasoconstriction

Question 3

How do arterioles control blood flow to capillary beds and what controls this?

Answer 3

Thick rings of smooth muscle called precapillary sphincters can contract closing off capillary beds under control of the medulla

Question 4

Structure of capillaries

Answer 4

• single layer of endothelial cells with pores held together by a basement membrane
  Very permeable and huge surface area to volume ratio

Question 5

Why is there a low pressure in the veins?

Answer 5

Blood has lost all pressure in capillaries which then feed into the venules and veins

Question 6

Structure of vein

Answer 6

Outer layer of fibrous tissue
Thin middle layer of muscle and elastic tissue
Endothelium inner layer with valves
Large lumen

Question 7

How is blood pumped up the veins if there’s a low pressure?

Answer 7

Flow is helped by contraction of muscles in legs and abs which squeeze the veins forcing blood up

Question 8

Which blood vessels are lymph vessels most like?

Answer 8

Capillaries

Question 9

What remains in the blood in capillaries directly after leaving arterioles

Answer 9

Proteins, cells, platelets

Question 10

Describe the formation of tissue fluid

Answer 10

• at arterial end of the capillary bed the hydrostatic pressure of blood is high
• blood plasma and all the solutes are forced out except proteins cells and platelets
• this forms tissue fluid around the cells
• materials are exchanged between cells and the tissue fluid lowering the concentration of nutrients
• at the venous end the oncotic pressure (solute potential) is greater than the hydrostatic pressure so most the tissue fluid returns to the blood

Question 11

What happens to the excess of tissue fluid?

Answer 11

Drained into lymph vessels in capillary beds forming lymph

Question 12

What 2 pressures are essential in formation of tissue fluid?

Answer 12

Oncotic pressure and hydrostatic

Question 13

Give a list of the functions of the blood that are not to do with transport

Answer 13

Defence against pathogens
Tissue fluid formation
Clotting

Question 14

What is the difference between tissue fluid and lymph

Answer 14

Lymph has a much lower concentration of nutrients than tissue fluid as it has mostly been transported into nearby cells and more lipids from digestion system

Question 15

Functions of the lymphatic system

Answer 15

To drain excess tissue fluids
To absorb fats from the small intestine via lacteals in each villus
Part of the immune system, lymph nodes synthesis white blood cells

Question 16

What components make up the blood

Answer 16

• plasma
• red blood cells
• white blood cells
• platelets

Question 17

The plasma is the liquid part of blood that transports many compounds, name a few:

Answer 17

• glucose, amino acids, lipids
• urea lactic acid
• ions
• hormones
• proteins
• water
• heat

Question 18

What are the most abundant cells in the blood?

Answer 18

Erythrocytes (red blood cells)

Question 19

How is a red blood cell specialised?

Answer 19

• flexible biconcave structure with a large surface area
• no nuclei and mitochondria
• packed with haemoglobin

Question 20

What are granulocytes?

Answer 20

• cells with visible vesicles/granules
• they have lobed nuclei which is why they r called polymorphs
• eosinophils and basophils stimulate inflammatory response
• neutrophils are phagocytes

Question 21

Everything about agranulocytes

Answer 21

• large unlobed rounded nuclei
• monocytes and macrophages (phagocytes)
• lymphocytes small leukocytes for specific immune response