Week 6 - Blood

Question 1

What are the 3 functions of blood?

Answer 1

Transport
O2 & nutrients
Metabolic waste from cells
Hormones
Regulation
maintaining body temp
maintaining normal pH
maintaining fluid volume
Protection
prevent blood loss → clot formation
prevents infection

Question 2

What is blood made up of?

Answer 2

1. Plasma (55%) - water (90% changes with hydration) & solutes
2. Buffy Coat (<1%) - WBC and platelets
3. Erythrocytes (45%) - RBCs
   3 layers if centrifueged

TOTAL - 8% body mass
5-6l (M) 4-5l (F)

Question 3

What do RBCs look like and what do they do?

Answer 3

Biconcave disc providing large surface area for diffusion
It’s fn, to transport O2 and CO2 via Hgb
single RBC contains 250-280million Hb molecules, onto each of which 4 O2 molecules can attach

Question 4

What are the 3 plasma proteins and what do they do?

Answer 4

Albumin - made in the liver
Regulates osmotic pressure which is important for capillary exchange
Globulins
Immunoglobulins / gamma globulins
play a role in the immune system/ antibodies and signalling cells
Alpha & Beta globulins
transport proteins for lipids, metal ions and fat soluble vitamins
Fibrinogen
Large protein, transformed for thrombin to fibrin, which forms threads, catches platelets and forms a clot

Question 5

How can RBCs stop a bleed (haemostasis)?

Answer 5

Primary
platelet plug - platelets release Von Willebrand Factor (VWF) which binds with collagen to help plug the gap
stop bleeding if gap small enough
Secondary
clotting factors are released. Fibrinogen transformed for thrombin to fibrin, which forms threads, catches platelets and forms a clot

Question 6

How are blood types formed and determined?

Answer 6

• A blood → Anti B antibodies
• B blood → Anti A antibodies
• AB → no antibodies
• O blood → both antibodies
• If the Rhesus factor (Rh) is present then the blood group is +ve, if not -ve - A+, AB-

Question 7

What happens if someone gets a blood transfusion of the wrong type?

Answer 7

1. agglutination (clumping) can occur- Ab in the recipient’s plasma can bind with the antigens in the donated blood causing RBCs to bind
2. another potential issue- haemolysis antigen / Ab complex activate complement proteins embedded within the membrane of the RBC causing the RBC to rupture. Freed Hb can cause kidney damage