Blood - lect 24

Plasma Components (4)

~5 liters of blood

~ 90% water

• Inorganic salts (electrolytes)

• Proteins

Blood Functions (3)

1. Transport

2. Fluid Balance

3. Pathogen Defense

Blood Composition

1. Cells

2. Plasma (55%)

Inorganic Salts (electrolytes) in Plasma Functions (3)

1. pH buffering

2. Osmotic balance

3. Ion regulation (Ca2+, Mg+, Na+)

Plasma Proteins (4)

1. Albumin – keeps water in blood (osmotic balance)

2. Immunoglobulins – antibodies

3. Apolipoproteins – transport fats

4. Fibrinogen – helps with blood clotting

Cellular components in blood produced in?

Produced multipotent stem cells in bone marrow

Three big groups of cells

1. Erythrocytes (RBC’s)

2. White Blood Cells (WBC’s)

3. Platelets

Erythrocytes (RBC’s) Structure (3)

• Biconcave shape (more surface area)

• No nucleus (in mammals) or mitochondria

• Contain hemoglobin

Erythrocytes (RBC’s) Function

Carry/Transport O2

White Blood Cells (WBC) (Leukocytes) Function

Immune defense - Fight bacteria, viruses, parasites

Leukocytes

White Blood Cells

Erythrocytes

Red Blood Cells

Platelets Structure (2) and Function(1)

• Formed from pinching off parts of large cells in bone marrow cells

• No nucleus

• Help form clots to stop bleeding

Platelet Plug Formation (fast!) (5 steps)

1. Collagen fibers exposed

2. Platelet plug formation

3. Blood Vessel constricts

4. Platelets stick to collagen

5. Platelets attract more platelets

   (This is a temporary seal - a plug)

Fibrin Clot Formation (Permanent Seal)

This makes the clot strong and stable.

1. Clotting factors: Ca²⁺, and (2) platelet compounds are activated

2. Prothrombin (inactive enzyme) → converted to thrombin - catalyzed by vitamin K

3. Thrombin converts fibrinogen (soluble) → fibrin (insoluble fibers)

4. Fibrin makes a fibrin clot - long threads weaved into a net that trap blood cells

Fibrin Clot Formation Factors (2)

Ca²⁺ and platelet compounds

Plug formation Simple

1. Prothrombin → thrombin → fibrinogen → fibrin → fibrin clot

Clotting problems

1. Hemophilia

2. Thrombus

Hemophilia

Cannot clot, Missing clotting factor

Result: prolonged bleeding

Thrombus

Too much clotting, blocks blood flow

When a thrombus forms in your brain?

Can cause brain damage due to lack of oxygen

Thrombus in Brain Signs

look for stroke signs:

1. Face drooping

2. Arm weakness

3. Speech difficulty

Types of Defense Systems (2)

1. Innate Immunity

2. Adaptive Immunity

Defense system Function

Protects against foreign agents - All living things possess!

Innate Immunity Charact (3)

• Present from birth

• Non-specific (responds to many pathogens the same way)

• Fast acting

Adaptive Immunity Charact (3)

• Specific to particular pathogens

• Develops after exposure

• Slower but stronger and has memory

Innate Immunity – Barrier Defenses

Prevent pathogens from entering the body

Barrier Defenses types (4)

1. Skin:

Skin Microorganisms: good bacteria compete with harmful ones

Oil & Sweat glands: create acidic environment (pH 3–5)

2. Mucous: trap microbes at body openings

3. Ciliated cells: sweep mucus & trapped particles in respiratory tract

4. Stomach acid and enzymes: kills swallowed microbes

5. Lysozymes (in saliva, tears): break down bacterial cell walls

Cellular Innate Defense (internal defense) (4)

1. Phagocytic Cells with Toll-like receptors (TLR)

2. Natural Killer Cells (NK)

3. Antimicrobial peptides/proteins - complement system

4. Inflammatory Response

Phagocytic Cells

• Use Toll-like Receptors (TLRs) to detect common pathogen features:

TLR3: detects double-stranded RNA (viruses)

TLR4: detects lipopolysaccharides (bacterial membranes)

Engulf & digest pathogens via phagocytosis

TLR3 - Phagocytic Cells

Detects double-stranded RNA (viruses)

TLR4 - Phagocytic Cells

Detects lipopolysaccharides (bacterial membranes)

Natural Killer Cells (NK) (3)

1. Don't attack the pathogens

2. Recognize abnormal or cancerous cells in your body

3. Kill these cells by triggering cell death (apoptosis)

Antimicrobial Peptide/Proteins (1)

Complement System: group of proteins that enhance immune

Complement System

Group of proteins that enhance immune response. Warn nearby cells and help them block infection

Interferons

Proteins made by virus-infected cells

Inflammatory Response

1. Calls mast cells (heat, redness, pain, swelling)

2. Macrophages arrive and phagocytize pathogen

Mast cells

Release histamine and cytokines

Histamine & cytokines functions (3)

1. Dilate local blood vessels

2. Increase blood flow

3. Increase blood in interstitial fluid (edema)