Blood

Chapter 2.2

Blood• Blood is a connective tissue• Consists of plasma, red blood cells, platelets, and white

blood cells.• Blood carries oxygen and nutrients to the body.

Plasma

• Plasma is the fluid part of the blood.• Water, minerals, nutrients, sugars, and

other things• Red blood cells, white blood cells, and platelets are in plasma

Red Blood Cells (RBC’s)

• Erythrocytes• Take oxygen to every cell in the

body• Contains Hemoglobin

• Oxygen-carrying protein

There are about one billion red blood cells in two to three drops of blood. For every 600 red blood cells, there are about 40 platelets and one white cell

Platelets

• Platelets are fragments of larger cells found in the bone marrow.

• Platelets last 5-10 days, but are extremely important.• Platelets help stop bleeding by clumping together at the

site of a wound.

White Blood Cells... WBC’s (Most are made in the bone marrow. Some mature in the lymphatic system)

White blood cells are a line of defense. They destroy pathogens.

• What is a pathogen?

A pathogen is an infectious agent, or more commonly germ, such as a virus, bacteria, or fungus that causes disease to its host.

Fighting Pathogens

• White blood cells destroy in various ways:• Some engulf the invaders• Some produce antibodies that destroy certain

pathogens• Some clean up dead body cells.

Body Temperature Regulation

• When your body temperature goes up, blood vessels enlarge. Why?

• Heat can be transferred to your skin and evaporates. This cools you down!

Blood Pressure

• Blood pressure is the force

exerted by blood on the walls of arteries.

(Why not veins?)

• Veins are returning blood to the heart. The pressure is not near as great.

What are the Two numbers in BP?

• BP is usually given in two numbers. EX: 110/70mmHg• Systolic: Is the pressure exerted in large arteries when

the ventricle contracts.• Diastolic: Is the pressure exerted on the arteries when

the ventricle is relaxed.

Microscopic Views

Bird Blood

Cat Blood

Dog Blood

Fish Blood

Frog Blood

Snake BloodHuman Blood

Horse Blood

HIV/ADIS• HIV is the Human Immunodeficiency Virus.

• Can lead to Acquired Immune Deficiency Syndrome, or AIDS.

• damages a person’s body by destroying specific blood cells

• AIDS is the late stage of HIV infection• when a person’s immune system is severely

damaged and has difficulty fighting diseases and certain cancers

Toddler Cured of HIV