MODULE 8: BLOOD AND BODY FLUIDS

WHAT PERCENTAGE OF TBW IS IN ICF?

66% TBW

WHAT ARE THE TEO COMPONENANTS OF ECF?

• INTERSITITUAL FLUID (25% OF TBW)

• PLASMA (8% OF TBW)

MAIN ELECTROLYTES IN ECF?

• SODIUM (NA+)

• CALCIUM (CA2+)

• CHLORIDE (CL-)

• BICARBONATE PO43-

MAIN ELECTROLYTES IN ICF?

• POTASSIUM (K+)

• MAGNESIUM (MG2+)

• PHOSPHATE (PO43-)

What is osmolarity?

Number of solute particles per litre of solution

What happens to cells in a hypertonic solution?

They shrivel

What happens to cells in a hypotonic solution?

They swell or burst

How is osmolarity maintained?

Osmosis, transport proteins, Na⁺/K⁺ pumps

What are the three main functions of blood

1. transport

2. regulation

3. protection

What does blood transport?

Nutrients, gases, waste, hormones, proteins

How does blood regulate the body?

Controls temperature, fluid volume, pH

How does blood protect the body?

Prevents blood loss and fights infection

What are the components of plasma?

Proteins, nutrients, electrolytes, gases, hormones, wastes

What are the formed elements in blood?

Erythrocytes, leukocytes, thrombocytes

Function of erythrocytes?

Carry oxygen via haemoglobin

Function of thrombocytes?

Aid in clotting

Where are erythrocytes made and what stimulates their production?

Bone marrow via erythropoiesis, stimulated by EPO from kidneys

How long do erythrocytes live?

120 days

What happens to haem during RBC breakdown?

converted to bilirubin → processed by liver → excreted in bile

What condition results from excess bilirubin?

Jaundice

How many polypeptide chains in haemoglobin?

4 (2 alpha, 2 beta)

What does each chain bind?

One haem group with one iron atom

How many oxygen molecules can one RBC carry?

Up to 1 billion

What are the three stages of haemostasis?

1. Vascular spasm

2. platelet plug formation

3. coagulation

What converts fibrinogen to fibrin?

Thrombin

What triggers the intrinsic and extrinsic pathways?

Intrinsic: platelets + collagen; Extrinsic: tissue factor

What does clot retraction do?

Pulls wound edges together

What activates fibrinolysis?

TPA activates plasmin → breaks down fibri

What do WBCs do during healing?

Clear debris

What antibodies does blood type A have?

Anti-B

What blood type is the universal donor?

Type O

What blood type is the universal recipient?

Type AB

Why is Rh compatibility important in pregnancy?

Rh⁻ māmā + Rh⁺ pēpi → risk of anti-D formation → HDN

How is Rh sensitisation prevented?

Administer anti-D immunoglobulin after birth

3 steps of coagulation

1. Trigger process → Prothrombin activator

2. Prothrombin → Thrombin

3. Fibrinogen → Fibrin → Clot mesh

What antigens and antibodies does blood type A have?

A antigens on red blood cells, anti-B antibodies in plasma.

What antigens and antibodies does blood type B have?

B antigens on red blood cells, anti-A antibodies in plasma.

What does blood type AB have?

Both A and B antigens, no antibodies → universal recipient.

What does blood type O have?

No antigens, both anti-A and anti-B antibodies → universal donor

What does Rh+ mean?

The person has the D antigen on their red blood cells.

What does Rh− mean?

No D antigen. Can develop anti-D antibodies if exposed to Rh+ blood

Why is Rh− important in pregnancy?

A Rh− māmā carrying a Rh+ baby can develop anti-D antibodies, which may harm future Rh+ babies.