Respiration and Circulation CHAPTER 16

The Respiratory System ▪ Group of organs that exchange gases between the body and atmosphere. ▪ Breathing-movement of air into and out of the lungs ▪ Inhale oxygen ▪ Exhale carbon dioxide ▪ Called cellular respiration ▪ sugar+oxygen  carbon dioxide+water+ATP ▪ Cells use ATP to carry out functions

Organs of the Respiratory System ▪ Air enters through nose and mouth ▪ Ciliated cells (cells with hairs) capture dust and other debris ▪ Sweep them out ▪ In the throat, air passes through the pharynx ▪ A tube that receives air, food, and liquids ▪ A flap called the epiglottis flips to prevent food and liquids from entering the respiratory system ▪ From the pharynx, air passes into the larynx (voice box), then to a long tube called the trachea

Continued ▪ From the trachea, air passes into tubes called bronchi ▪ Bronchi split into 2 sides, 1 for each lung ▪ Inside the lungs, the bronchi branch into bronchioles ▪ At the end of the bronchioles are little pouches called alveoli ▪ This is where gas exchange occurs ▪ Carbon dioxide moves out of the blood, oxygen moves in

The Breathing Process ▪ Controlled by the nervous system ▪ Monitors the amount of O 2 and CO 2 in the blood ▪ When levels need adjustment, brain sends a signal to the diaphragm, causing it to contract ▪ When it contracts, it increases the volume of the lungs ▪ Physics: ▪ Air moves from high pressure to low pressure ▪ After contracting, the lungs have a lower pressure than the atmosphere ▪ Air rushes in the lungs ▪ Called inhalation ▪ Oxygen moves into the blood, carbon dioxide moves out ▪ When the diaphragm relaxes, air pressure is greater in the lungs than the atmosphere, so air rushes out ▪ Called exhalation

Respiratory Health ▪ Colds and flu affect the respiratory system ▪ Harder to breathe as the respiratory tract is inflamed and filled with mucous ▪ Bronchitis is an inflammation of the bronchi ▪ Pneumonia is a buildup of fluid in the alveoli ▪ Makes gas exchange difficult ▪ Asthma is due to swollen airways ▪ Usually due to dust, pollen, etc. ▪ Emphysema damages the alveoli, making gas exchange hard ▪ Lung cancer makes gas exchange difficult

The Circulatory System ▪ Group of tissues and organs that carries materials to and from the body’s cells ▪ Transports food, water, oxygen, and other things ▪ Aids in the elimination of wastes ▪ The heart is the primary muscle ▪ Pushes and receives blood ▪ Usually beats times per minute ▪ Slows during sleep, increases during activities

Parts of the Heart ▪ 4 chambers, separated by valves ▪ Blood enters through the vena cava ▪ Goes to the right atrium ▪ Atrium contracts, sending blood to right ventricle ▪ Right ventricle contracts, sending blood to lungs via pulmonary arteries ▪ Blood returns from lungs via the pulmonary veins to the left atrium ▪ Left atrium contracts, sending blood to the left ventricle ▪ Left ventricle contracts, sending blood to the body via the aorta

Blood Vessels ▪ Arteries, including the aorta, carry oxygen rich blood to the body ▪ Arteries branch throughout the body, and split into arterioles ▪ Arterioles branch further into capillaries ▪ It is in the capillaries that material move out of the vessels and into the cells ▪ The blood loses oxygen and must return to the heart to get more ▪ Capillaries join together into venules ▪ Venules join together into veins ▪ The veins all join to form the vena cava, which carries blood back into the heart

Blood Pressure ▪ Pressure of the blood on the walls of the blood vessels ▪ Measured as a fraction, sort of… ▪ Systolic pressure (maximum) over diastolic pressure (minimum) ▪ The numbers are the pressure in mmHg (millimeters of mercury-the common scientific unit for any type of pressure) ▪ Normal is 120/80 ▪ High blood pressure (either number being greater) is called hypertension ▪ Low blood pressure (less than 90/60) is called hypotension

Atherosclerosis ▪ Buildup of plaque in arteries ▪ Interferes with blood flow and can form a clot ▪ If deposit breaks free, it can block blood flow ▪ Can cause heart attacks and stroke ▪ In each, part of the organ dies or is damaged from lack of oxygen ▪ All circulatory system disorders have genetic and environmental components ▪ Eating right and exercising both help ▪ Avoiding smoking helps a lot

Blood ▪ Always red ▪ Never blue ▪ Tissue ▪ 3 main jobs: ▪ Transportation of materials (food, water, oxygen, carbon dioxide, etc.) ▪ Protection (fighting infection, repair of wounds) ▪ Temperature regulation ▪ When you are warm, blood vessels expand and release heat to cool you down ▪ When you are cold, blood vessels contract and trap more heat

Blood Parts ▪ 3 types of cells ▪ Red Blood Cells (a.k.a. erythrocytes) ▪ Contain hemoglobin, which binds to oxygen ▪ Flattened disk shape ▪ White Blood Cells (a.k.a. leukocytes) ▪ Several types ▪ Protect against infection ▪ Fewer in number than RBC ▪ Platelets ▪ Small, irregularly shaped cells ▪ Plug wounds and stop the bleeding ▪ Very numerous ▪ Plasma-Yellow, liquid part of cells ▪ 90% water, with molecules dissolved in it

The Lymphatic System ▪ Part of the immune system ▪ Helps destroy pathogens that enter the body ▪ Works along with the circulatory system ▪ 4 main functions: ▪ Absorb fluid around cells ▪ Transports fats from the digestive system to the blood ▪ Filters pathogens out of tissues ▪ Fights of illnesses

Parts of the Lymphatic System ▪ Lymph ▪ Made of water, WBCs, and dissolved molecules ▪ Lymph vessels ▪ Absorb and transport lymph ▪ Transported by contractions of muscles, not by the heart ▪ Lymph nodes ▪ Filter particles from the lymph ▪ Store WBCs ▪ Swell during infection due to production of WBCs ▪ Swelling decreases after illness as production is decreased

Continued ▪ Bone marrow ▪ Bone marrow forms WBCs ▪ Thymus ▪ Organ that matures WBCs ▪ Spleen ▪ Recycles and stores blood cells ▪ Tonsils ▪ Clusters of lymph tissue ▪ In throat ▪ Trap and destroy pathogens ▪ When they do this, they swell ▪ If this happens often, they may need to be removed