Chapter 20

Respiration & Excretion

Ch 20.1 – The Respiratory System

A. Functions – supply oxygen to the body

1. Breathing – the movement of the chest that brings air into the lungs and removes waste gases

2. (Cellular) Respiration – oxygen used by cells to release energy from glucose (food)

a) waste products of resp. are CO2 & H20

B. Organs of the respiratory system

1. Pharynx (throat) – tubelike passageway used by food, liquid and air

a) lower end has tissue flap called the epiglottis to prevent food or liquid from entering airway

2. Larynx – small area in neck region below pharynx which houses the vocal cords

3. Trachea – AKA windpipe; tube leading

down to lungs held open by rings of

cartilage, and lined with cilia and mucous

4. Bronchi – 2 short tubes at the end of the trachea that go into each lung then branch into smaller tubes called bronchioles

5. Lungs – organs at the end of bronchi

tubes that contain small clusters of air

sacs called alveoli at end of each bronchiole

a) Alveoli are surrounded by capillaries

which is where gas exchange takes place

in the lungs

C. Why do you breathe?

1. Signals from brain tell muscles in abdomen to contract and relax

a) If oxygen levels in blood decrease and CO2 levels increase your breathing rate

increase

b) If 02 increases and CO2 decreases your breathing decreases

2. Diaphragm – muscle beneath lungs that contracts and relaxes to move air into and out of lungs

The Iron Lung

D. Diseases and Disorders

1. Colds, Influenza – viruses that affect the upper respiratory system (nose, mouth, pharynx & larynx)

2. Bronchitis – bacterial infection that

irritates the bronchial tubes leading into

the lungs; coughing and lots of mucus result as body’s method of removing infection

a) Chronic Bronchitis – ongoing from repeated exposure to irritating substances

3. Pneumonia – infection of the alveoli that

may be caused by bacteria or virus

spreading from upper respiratory system

4. Emphysema – disease of the alveoli

which causes them to enlarge then

collapse and malfunction

a) causes shortness of breath due to lack of oxygen and can often lead to heart problems

5. Lung Cancer – uncontrolled cell growth in lung tissue

a) smoking is greatest contributing factor

b) tar and other ingredients in cigarette smoke are carcinogens

6. Asthma – disorder in which bronchi tubes contract quickly due to allergic reaction

a) may be caused by foreign substance (pollen, smoke, foods etc) or stress

b) causes shortness of breath, wheezing or coughing

Ch 20.2 – The Excretory System

A. Functions – remove body wastes

1. Occurs through integumentary, digestive, circulatory, respiratory and urinary systems

B. Urinary System – gets rid of cell wastes

that accumulate in the blood and controls blood volume

1. Organs:

a) Kidneys – filters blood for waste products and excess water through tubes called nephrons

b) Ureters – Tubes that pass urine down

from each kidney

c) Bladder – elastic organ that collects and holds urine drained from ureters

d) Urethra – small tube that passes urine

out of the body once bladder is full

2. Hypothalamus – part of the brain that regulates the amount of water in blood

a) If blood has too much water, hypothalamus tells kidneys to increase urine production

b) If blood has too little water, hypothalamus tells kidneys to decrease urine production

C. Other organs of excretion

1. Liver – filters blood and produces a chemical called urea which kidneys pull out and put in urine

D. Disease and Disorders

1. Infections – bacterial infections may occur in urethra or bladder

a) Urethra and ureters may become blocked interrupting the flow of urine

b) May be detected by urine test

c) If left untreated bacteria may spread and cause kidney damage

2. Kidney Stones – hard mass developed

from crystals forming in the urine

3. Kidney Failure

a) A person with one kidney can live normally

b) If both fail, the person will need a dialysis machine to filter their blood