Unit 10-Human Body

Chapter 37

Circulatory and Respiratory Systems

Functions of the Circulatory System

• Transport of…– Respiratory gases– Nutrients– Wastes– Hormones

• Defense from…– invaders– blood loss

Blood vessels

• Arteries– Carry blood away from heart– Thick, muscular: under pressure

• Veins– Carry blood toward the heart– Thin, little muscle; valves

• Capillaries– Smallest, one cell thick & diameter– Where exchanges occur

Blood components

• Plasma• Yellow liquid

(90% water)

• Transports…– Food– Wastes– Hormones– Fibers , etc

Blood components

• Red blood cells

(erythrocytes)• Small, biconcave

cells without nucleus• Hemoglobin =

red pigment, gives ability to…

• Transport oxygen

Blood components

• White blood cells(leucocytes)

• Large, clear, ameboid, cells with nucleus & granules

• Fight infection (by phagocytosis)

Blood components

• Platelets(thrombocytes)

• Smallest; cell fragments

• For clotting only

Heart

• Pericardium – sac surrounding heart,

to prevent friction

• Chambers:• Atria (right & left) = receive blood • Ventricles (right & left) pump blood• Valves = prevent backflow of blood

– Between atria & ventricles– Between ventricles & arteries

Lymphatic System

Lymphatic System Function

• Series of vessels that collect fluids lost by blood and returns the blood to the circulatory system

• Main organs: – thymus, spleen. lymph nodes, lymph vessels

• Works in conjunction with the immune system

Lymph Organs

Primary function: – to trap and filter

microorganisms that may have invaded the body

(May become enlarged when many microbes are trapped, indicating illness)

Anatomy of the Respiratory System• Nasal cavity

– To warm, moisten and filter air

• Pharynx – Throat; for transporting

air and food

• Epiglottis – Cartilage flap; to prevent food

from entering lungs

• Larynx – voice box: voice pitch

controlled by… – tension & thickness of cords

The cartilages of the larynx

The vocal folds

The epiglottis

Anatomy of Respiratory system• Trachea

– Windpipe; with cartilage rings to prevent collapse

• Within lungs:– Bronchi = 2 large branches– Bronchioles = smallest

branches into...– Alveoli =

tiny air sacs where gas exchange occurs

• Diaphragm – breathing muscle

Breathing

• Inspiration

– Diaphragm contracts, chest increases, pressure decreases, air comes in

• Expiration

– Diaphragm relaxes, chest decreases, pressure increases, air forced out

Types of Respiration

• External – Within lungs– Oxygen enters blood,

CO2 exits blood

• Internal – Within body tissues– Oxygen enters cells,

CO2 exits cells