Blood and immunity

Name the 4 components in blood

1. Plasma

2. Red blood cells

3. White blood cells

4. Platelets

Plasma

Plasma is a straw colored liquid consisting mostly of water.

Function of plasma

Transports dissolved substances:

• carbon dioxide

• digested food

• urea

• hormones

• heat

Why does plasma contain a lot of heat energy?

important for maintaining a constant temperature for enzymes.

Blood plasma and carbon dioxide

• Carbon dioxide released during respiration.

• Carried in the blood to the lungs, where it is excreted.

Blood plasma and digested food

• Glucose and amino acids are transported in the plasma to cells.

• Glucose and amino acids are then respired or converted into new compounds.

Blood plasm and Urea

• Urea is formed from the breakdown of proteins.

• Carried to the kidney’s for excretion.

Blood plasma and hormones

• Hormones are created by glands.

• Released into the bloodstream to work on target cells.

Red blood cells

Transports oxygen around the body.

Adaptations of red blood cells

1. Biconcave shape - increases surface area for gas exchange.

2. Hemoglobin - contains iron (and protein) that binds to oxygen.

3. No nucleus - increases space for hemoglobin to occupy.

4. Small and flexible - allows red blood cell to squeeze through capillaries.

White blood cells

• Controls the immune system (fights against foreign pathogens.)

• Made in the bone marrow

White blood cells - Phagocytes

• engulf and digest pathogens

• release enzymes to digest them

• target all foreign cells (they are non-specific)

White blood cells - Lymphocytes

• produce and release antibodies to neutralize pathogens.

• antibodies immobilize the pathogen

White blood cells - Agglutination

antibodies bind to pathogens and cause them to clump together.

White blood cells - antitoxin

• neutralize harmful substances released by pathogens.

• this response is specific for each pathogen.

First stage of immunity

• takes several days for specific antibodies for a pathogen to be created.

• human develops symptoms.

Second stage of immunity

• Some lymphocytes develop into memory cells.

• memory cells contain the information to create the antibody for a specific illness.

• if the human is re-infected with the same pathogen, these antibodies will be made more rapidly and in greater number.

Pathogen mutation

• pathogens change their shape so antibodies will not bind.

• leads to several strains of pathogen (eg. Covid-19)

Platelets

• fragments of cells involved in blood clotting.

What do platelets do when you get a cut?

• when skin becomes damaged, platelets become sticky and adhere to the damaged region (forms a solid.)

• cause vasoconstriction - reduces blood flow through damaged region.

Fibrinogen

• soluble protein

• converted into fibrous

Fibrin

• fibrous protein

• fibrin fibres form a mesh across the wound and traps blood cells to form a scab.

• prevents excessive blood loss and the entry of pathogens into the blood stream.

What is a vaccine?

a dead of modified pathogen is injected into the patient.

What do vaccines stimulate?

• the immune response

• if the disease is contracted, symptoms will NOT develop.

Primary immune response to antigen

occurs after a delay.

Secondary response to antigen

response is faster and larger.