Circulation and Gas Exchange

. Respiratory system - draws in gases from the environment, intakes O2 and outputs CO2

· Circulatory system - transports O2, CO2, nutrients, hormones, and blood cells

Delivers O2 to cells for cellular respiration, and removes waste CO2

· Ventilation - movement of air, or water, through organs of gas exchange, like lungs or gills

. Gas exchange - diffusion of O2 and CO2 at respiratory tissue surface

. Circulation - transport of diffused gases throughout the body

· Cellular respiration - O2 is final electron acceptor of ETC, and CO2 is byproduct of glycolysis and citric acid cycle

. Pulmonary circulation - carries deoxygenated blood from the heart to the lungs, and oxygenated blood to the heart

Deoxygenated blood carrying CO2 from tissues is moved from the heart to the lungs

Waste CO2 diffuses into the lungs, where it is exhaled

Inhaled O2 diffuses into the blood, and the oxygenated blood return to the heart

. Systemic circulation - oxygen-rich blood moves through arteries to tissues throughout the body

O2 diffuses into cells, to be used in the mitochondrial matrix

Delivers nutrients and carries away waste from tissues

Deoxygenated blood carrying CO2 returns to the heart from the tissues

. Endothelium - epithelial tissue that lines the interior surface of blood vessels and lymphatic vessels

. Arteries - transport blood away from the heart, oxygenated in systemic loop, deoxygenated in pulmonary loop

- Have elastic walls, and are wrapped in smooth muscle allowing them to change their diameter

- Arterioles - small arteries that branch off by capillary beds, have smooth muscle, and smaller diameter

. Veins - transport blood to the heart, deoxygenated in systemic loop, oxygenated in pulmonary loop

- Have less smooth muscle than arteries, but many veins run through skeletal muscles

- Contain valves to prevent backflow of blood, since pressure is lower than in arteries

- Venules - converge to form veins, formed from capillaries converging

. Capillaries - tiny vessels with walls only one-cell thick with a diameter roughly equivalent to that of a red blood cell

Only site of exchange between blood and tissues, endothelial tissue with no smooth muscle

Capillary beds - diffuse networks of capillaries running through tissues

- Pre-capillary sphincters - control blood flow to specific capillary beds

. Heart- muscular organ that contracts to generate pressure waves that push blood through blood vessels

Atria - receive blood from veins

Ventricles - receive blood from atria, and pump blood into arteries

Atrioventricular valves - prevent backflow from ventricle to atrium, tricuspid valve on right, mitral valve on left

Semilunar valves - prevent backflow from arteries to ventricles, pulmonary valve on right, aortic valve on left

- Heart murmur - blood moves back across a valve, often due to damage or infection in valve

. Pulmonary artery - delivers deoxygenated blood from the heart to the capillary beds in the lungs

. Pulmonary veins - delivers oxygenated blood from the lungs back to the heart

. Aorta - delivers oxygenated blood from the heart to the tissues

. Venae cava (superior and inferior) - delivers deoxygenated blood to the heart from capillary beds in the body's tissues

. Pulmonary circulation - right atrium > right ventricle > pulmonary artery > lungs > pulmonary vein > left atrium

Oxygenates the bloods in capillary beds at the alveoli of the lungs, gets rid of waste CO2

. Systemic circulation - left atrium > left ventricle > aorta > body tissues > venae cava > right atrium

Delivers O2 to tissues via capillary beds throughout the body, and picks up waste CO2

. Pharynx - throat area behind the mouth, shared passage way for air, food, and water

. Trachea - brings air from pharynx to lungs, supported by c-shaped cartilage rings

Larynx - beginning of the trachea, contains the vocal folds

Primary bronchi - first branches into the lungs

. Bronchi - branches from the primary bronchi that diffuse through the lungs, supported by cartilage

Bronchioles - smallest branches of the bronchi, supported by smooth muscle

. Lungs - organs of respiration that inhale air to absorb O2, and exhale waste CO2 from cellular respiration

Alveoli - grape-like ends of the smallest bronchioles where gas exchange occurs between air and blood

- Thin, aqueous interface between air and surrounding capillary bed

- Surfactant - mix of phospholipids and proteins produced by some alveoli to reduce surface tension

. Diaphragm - sheet of muscle that separates thoracic (chest) and abdominal (belly) cavities. Blood - fluid that flows through blood vessels, transports nutrients and wastes, and performs gas exchange with tissues

. Plasma - special extracellular matrix that composes the liquid part of blood

Made of water, electrolytes, organic compounds, and dissolved gases

. Platelets - small cell fragments that are involved in the blood clotting wound response

Rapidly plug holes, while other factors are recruited to help seal the wound site

Thrombus - clot that forms in a blood vessel blocking blood flow

. White blood cells (leukocytes) - immune system cells that help identify and fight infections

. Red blood cells (erythrocytes) - carry O2 from the lungs via hemoglobin, lack nuclei and organelles at maturity

Ervthropoietin - hormone secreted bv the kidnev to stimulate RBC production in bone marrow

. Respiratory pigments - molecules that increase the oxygen-carrying capacity of blood, change color from O2 binding

Hemoglobin - protein made of 4 polypeptide subunits that contain hemes to bind oxygen

- Heme- iron-containing cofactor with porphyrin ring that is reduced/oxidized to transport O2 in RBCs

Myoglobin - primary pigment of skeletal muscles, contains only 1 heme, binds O2 tighter than hemoglobin

Sickle-cell disease - abnormal form of hemoglobin aggregates in RBCs, distorting shape, and inhibiting functions

. Lymphatic system - network of lymphatic vessels that carry lymph toward the heart

Drains plasma from interstitial fluid, and plays important role in the immune system

Lymph - clear fluid that circulates through lymphatic system, forms when interstitial fluid enters lymphatic ducts

Lymph nodes - organs of the lymphatic system that are critical to immune function

Spleen and thymus important organs of lymphatic system