30.1 and 30.2 Respiratory and Circulatory functions and Gas Exchange

Cardiovascular System  Heartbeat is ultimate sign of “life”  No matter your state of consciousness, your heart beats and your blood flows (sleeping, awake, during activity)

Circulatory System  The body system that transports blood and other materials.  Brings vital supplies to the cells and carries away wastes.

Respiratory System  System in which gas exchange takes place.  Moves gasses into and out of the blood.  Brings O 2 into the body and expel CO 2 and water vapor.

Parts of the Respiratory System  Nose and mouth: brings in air, moistens, warms, and cleans it as it crosses hairs mucus linings.  Epiglottis : covers the trachea when you swallow  Trachea : Divides into two bronchi bringing air into each lung.  Lungs : absorb O2 from the air.  Alveoli : Tiny air sacs where gas exchange occurs.  Diaphragm : muscle at the base of the rib cage helps expand the lungs.

Parts of the Circulatory System  A Fluid  A Pump  Tubes

Fluid  Blood : Mixture of cells, cell fragments, and plasma.  Average person has about 5 liters of blood.

Pump  Heart : Muscular pump about the size of your fist that pushes blood to all parts of your body.  Takes about 60 seconds for blood to circulate from the heart throughout the body and get back to the heart.

Tubing  Arteries : carry blood away from the heart.  Veins : carry blood towards the heart.  Capillaries : Tiny blood vessels that transport blood to and from the cells of the body.

Additional function of the Circulatory System  1. Helps maintain body temperature.

30.2 Respiration and Gas Exchange Key Concept The respiratory system exchanges oxygen and carbon dioxide

Gas Exchange  Gas Exchange occurs in the alveoli of the lungs  Recall cell respiration  C 6 H 12 O O 2 → 6 CO H 2 O  Gas exchange in the lungs is based on 3 principles:  1. O2 and CO2 are carried by the blood  2. Gases move by diffusion  3. The lining of the alveoli must be moist for diffusion

Gas Exchange  When you inhale, air flows from the bronchi  bronchioles  alveoli  In the alveoli, the respiratory and circulatory systems come together  All of the alveoli give the lungs a surface area of about 100 square meters

Gas Exchange  Diffusion of Oxygen (O2):  Blood Capillaries surround the alveoli  O2 is higher in the alveoli than in the capillaries  From breathing  Thus, O2 diffuses from the alveoli into the capillaries  Red Blood Cells pick up the oxygen in the lungs and deliver it to the body  Oxygen is bound to an iron-rich protein molecule called hemoglobin  The iron is what makes blood red

Gas Exchange  Diffusion of Carbon Dioxide (CO2)  CO2 is higher in blood than in alveoli  Due to cell respiration  Thus, it diffuses into the alveoli and you breathe it out

Gas Exchange and the Nervous System  Regulated/Monitored by the brain stem  Medulla Oblongata and Pons  Sensors in the circulatory and respiratory systems send signals to the brain.

Respiratory Diseases  Damage to the respiratory system makes gas exchange more difficult  Emphysema is a lung disorder caused mainly by smoking whereby alveoli are destroyed  Asthma causes the bronchioles to constrict due to muscle spasms  Cystic Fibrosis is a genetic disease that causes the lungs to produce a thick, sticky mucus