Systems Flashcards
DIGESTIVE SYSTEM
Most digestion occurs in small intestine
Lipids, carbohydrates, and any remaining products are digested in small intestine
Sections of small intestine
Duodenum: enzymes are added, digestion beings
Jejunum: digestion continues and some nutrients are absorbed
Ileum: majority of nutrients are absorbed
Villi
small finger like projections across small intestine that increase surface area for absorption
Within each villus there’s a section of capillaries
All nutrients except digested fats enter the bloodstream through the capillaries.
Digested fats are transported through small vessels called lacteals
The digested fats are transported to the lymphatic system and then into the bloodstream
Passive transport
movement of materials across cell membrane without the use of energy
Simple diffusion: movement from area of higher concentration to lower
Osmosis: water molecules diffuse across a selectively permeable membrane from higher concentration to lower concentration
Facilitated diffusion: diffusion of molecules through transport proteins
Active transport
movement of materials across a cell membrane from an area of lower concentration to an area of higher concentration, using energy provided by the cell.
Special transport proteins embedded in the cell membrane that require energy to move materials through the membrane (for example, its required when molecules are too large to diffuse on their own or if they have strong/uneven electrical charges)
ACCESSORY ORGANS
Liver: produces bile, breaks down fats, largest internal organ
Gallbladder: stores bile, decreated bile to duodenum through bile duct
Pancreas: Produces juice that contains enzymes and insulin which maintain blood sugar levels
RESPIRATORY SYSTEM
Oxygen diffuses from the lungs into the bloodstream. Carbon dioxide diffuses from the bloodstream into the lungs.
Oxygen diffuses from bloodstream to cells, carbon dioxide diffuses from cells to bloodstream.
Each cluster of alveoli is surrounded by capillaries. Alveoli have thin membrane for the sake of facilitating diffusion.
Breathing a.k.a. VENTILATION works like this:
Air pressure inside lungs is lower than atmospheric pressure (resulting in air rushing into the lungs)
Air pressure inside the lungs is higher than atmospheric pressure (resulting in air rushing outta the lungs)
Air flows from area of high to low concentration.
Diaphragm contracts to increase volume of thoracic cavity causing air to rush into lungs, then
Diaphragm relaxes and pushes up on the lungs, causing air to rush out.
Blood components
Plasma = matrix for blood cells, helps maintain water to blood volume Erythrocytes= carry oxygen to cells (hemoglobin). And also carries iron. Platelets = cause clotting to damaged vessels Leukocytes = protect body vs infection
CIRCULATORY SYSTEM: two kinds of circuits
Two kinds of circuits:
Pulmonary circuit: blood circulating to lungs to absorb oxygen then to heart
Systemic circuit: blood circulating the oxygenated blood to rest of body
Three kinds of blood vessels
Arteries: carry oxygenated blood away from heart.
Veins: carry deoxygenated blood to heart
Capillaries: link veins and arteries, exchange materials between the blood and other body cells
Vasodilation
relaxation of smooth muscles, increase diameter of blood vessels and increasing blood flow for the purpose of cooling blood by letting it lose thermal energy to surrounding environment
Vasoconstriction
contraction of smooth muscles, decreasing diameter and warming the blood by preventing thermal loss
Oxygen and nutrients diffuse from blood into tissue, carbon dioxide and other waste diffuse into capillaries. Capillaries are regulated through precapillary sphincters.
