* involves cellular respiration (remember aerobic and anaerobic respiration to produce adenosphine triphosphate)
* involves organismal respiration (the actual act of breathing!; gas exchange--oxygen in and carbon dioxide out


the respiratory system is composed of a network of passageways which permit air to flow from the external environment to the internal environment


1) Nasal Cavity:

* air enters the body through the nostrils and winds up in these passageways
* lined with a ciliated mucus membrane which filters, warms, and moistens the air

2) Pharynx:

* where the oral cavity and the nasal cavity meet (when you breathe through your mouth, air enters here...)

3) Trachea:

* main airway in the human respiratory system
* contains rings of a tough tissue (cartilage) keep this passageway open
* also lined with a ciliated mucus membrane to remove microscopic particles and sweeps them towards the pharynx

A) Larynx--

* otherwise known as the voice box
* structure made of cartilage found at upper end of the trachea
* when air passes over it, it vibrates

B) Epiglottis--

* flap of tissue that covers the trachea when you swallow so food doesn't go in

4) Bronchi:

* two major subdivisions that branch off the trachea
* lined with ciliated mucus membranes
* ringed with cartilage
* each bronchus extends to the lungs where the tubes become smaller

5) Bronchioles:

* smaller and smaller passageways that extend from each bronchus
* found in the lungs
* lined with ciliated mucus membranes
* is NOT ringed with cartilage

6) Alveoli: END OF THE LINE

* the air sac that is surrounded with capillaries for gas exchange
* is the functional unit for gas exchange!


* each bronchus with its bronchioles and alveoli are called a lung
*has a thin protective membrane over the entire organ


the lungs are highly elastic (flexible) and respond to the actions of the diaphragm and the rib cage

A) Diaphragm:

* the wall of muscle that lies under the lungs

B) Rib Cage:

* the bones and cartilage which protect the heart and lungs

Movements in the diaphragm and the rib cage cause pressure changes in the chest cavity which moves air into and out of the lungs. The movement of air into and out of the lungs is called breathing! As the diaphragm moves down, it causes the rib cage to move out. This causes a vacuum (suction) to form, drawing air into the body. When the diaphragm moves up, the rib cage moves in, which pushes air out.


1) In the blood, oxygen is carried by the red blood cells as oxyhemoglobin (this is just oxygen bonded to hemoglobin).

2) At the body cells, this oxygen leaves the hemoglobin by easily diffusing through the capillaries.

3) The cells can now carry out cellular aerobic respiration at the mitochondria for energy.

4) The end products (metabolic wastes) of cellular respiration, carbon dioxide and water) now diffuse back out of the cells into the blood.

5) Carbon dioxide is carried in the blood plasma in the form of bicarbonate ion (CO3)

6) These molecules then diffuse out of the blood through the walls of the capillaries which surround the alveoli and then are exhaled.


1) Bronchitis:

* an inflammation of the membranes of the bronchial tubes

2) Asthma:

* an allergic response characterized by the constriction (narrowing) of the bronchial tubes
* can be caused by many different factors
* medications and inhalers are used to open up the respiratory passages

3) Emphysema:

* a general deterioration of the lungs
* alveoli are enlarged and stiff (and can't function) which reduce the lung capacity for air

4) Pneumonia:

* a condition where the alveoli become filled with fluid, preventing the normal exchange of gases
* can be life threatening

5) Lung Cancer:

* when tumors (abnormal masses or growths of cells or tissues) form in the lungs as a result of irregular and uncontrollable cell growth


Human Respiration, Excretion, and Locomotion

a nice overview of all things related to the human respiratory system
alveoli equals more surface area--watch how
a nice review of how your lungs work
Environmental Tobacco Smoke and Lung Development Activity
eeewwww-- smokers lung


the life function that involves the removal of metabolic wastes

  1. aerobic respiration produces water and carbon dioxide
  2. anaerobic respiration produces lactic acid or alchohol and carbon dioxide
  3. dehydration synthesis produces water
  4. protein metabolism produces nitrogenous wastes
  5. other metabolic processes can produce salts, oils, etc.

remember, the removal of metabolic wastes, excretion, should not be confused with the removal of digested or indigestible food, egestion!

I. What organs do what?

A) Lungs

* are responsible for the excretion of carbon dioxide and water (waste products of cellular respiration)
* these are removed as gases during the process of exhalation

B) Liver

* recycles worn out red blood cells
* produces urea (a semi-toxic nitrogenous waste) from the breakdown of amino acids (contains nitrogen)

C) Sweat Glands (Skin)

* water (98%), salts, and a small amount of urea diffuse from the blood into sweat glands
* excreted through the process of perspiration (sweating!)
* main job of sweating is to maintain body temperature (cool down)

D) Kidneys (The Human Urinary System)

* site of most urea excretion
* controls the concentration of most of the body fluids

ALVEOLI (in the lungs) are the functional unit of gas exchange...


NEPHRONS (in the kidneys) are the functional unit of excretion


1) Arteries bring blood to the nephron so that material dissolved in the plasma can be FILTERED AND REABSORBED.

2) There is a ball of capillaries (small blood vessels) in the nephron called the glomerulus. This FILTERS OUT water, salts, urea, amino acids, and glucose (everything) into Bowman's capsule, which is a collecting tube.

3) As the materials move through the many tubes of the nephron, minerals, nutrients, and water (good stuff) are all REABSORBED BACK IN.

4) Veins carry the "filtered" blood away from the nephron.

5) Whatever was left in the collecting tubes is urine and will be excreted via the following pathway.


i) Kidneys
* place of filtration and reabsorption

ii) Ureter
* urine flows from the collecting tubes in the kidneys to the ureter (a pipe)

iii) Urinary Bladder
* urine flows from ureter to this place where it is temporarily stored

iv) Urethra
* periodically, urine is EXCRETED from the bladder through the urethra


1) Kidney Failure (Kidney Diseases)

* a general term that describes any condition which results in the malfunctioning of the kidney or nephron
* can be caused by physical trauma or high blood pressure

2) Gout

* when URIC ACID (the non-toxic nitrogenous waste) is produced and deposited in the joints (where two bones meet)
* leads to an inflammation of the joints, which is similar to arthritis


Human Respiration, Excretion, and Locomotion

a nive review of the human urinary system


the life function that involves the moving of place to place


1) Bones:

* 206 in the human body
* arranged in an internal skeleton--an endoskeleton
* supports and protects certain body structures
* anchorage sites for muscle action and movement
* produces red and white blood cells in bone marrow (in the center of larger bones)

2) Cartilage:

* a flexible connective tissue
* cushions joints (reduces wear and tear)
* makes joints more flexible
* lightweight support

CARTILAGE IN EMBRYOS: makes up most of skeleton; changes to bone over time

CARTILAGE IN ADULTS: found at the ends of bones, between the vertebrae, in nose,
ears, and trachea

3) Muscles:

* have the ability to contract (get smaller)
* 3 main types:

A) Skeletal Muscle-

* is striped or striated in appearance
* moves the bones of the skeletal system
* controlled by somatic nervous system
* FLEXORS bring bones together
* EXTENSORS moves bones away from each other

B) Smooth (Visceral) Muscle-

* no stripes
* control involuntary actions such as peristalsis, arterial pulse, breathing (diaphragm), and other internal organs

C) Cardiac Muscle-

* have stripes
* control the involuntary contractions of the heart

4) Tendons:

* connective tissue that connects muscles to bones

5) Ligaments:

* tough elastic connective tissue that connects bones to bones at movable joints such as the elbow, fingers, knees, between vertebrae


1) Arthritis

* an inflammation of the joints; can be quite painful

2) Tendinitis

* an inflammation of the tendon, usually at the point where the muscle meets the bone
* very common in athletes

3) Broken Bones

* many different types of breaks can happen such as a simple, complex, spiral, greenstick, and stress fracture

Human Respiration, Excretion, and Locomotion

muscles and bones--need I say more?
get an idea of the three types of muscles