Circulatory and digestion

• heart


  double pump system to move blood in two separate pathways
• pulmonary circulation (2)


  - responsibility of right side of heart

  - from heart -> lungs
• systemic circulation (3)


  - responsibility of left side of heart

  - heart -> body

  - thicker muscle wall; does more work
• blood vessels (2)


  - blood from heart -> tissue -> heart

  - arteries, arterioles, capillaries, venules, veins
• arteries (5)


  - blood away from hearts

  - carries oxygenated blood except pulmonary artery

  - 3 layers ( outer connective, inner endothelium, middle thick elastic and muscle fibers)

  - elastic layer allows for expansion when blood pumps through

  - have own blood supply
• arterioles (3)


  - smaller arteries

  - less elastic fibers, has circulatory muscle under involuntary control

  - when muscle contracts; smaller, relaxes; larger
• capillaries (3)


  - one cell thick

  - in beds and networks across body, highly controlled blood flow

  - allows for gas and nutrient exchange between blood and cells

  ​
• venules (3)


  - drains blood from capillaries

  - carries blood to heart

  - valves preventing backflow
• veins (4)


  - deoxygenated blood towards the heart except pulmonary vein

  - resouvoir for blood (50%)

  - thinner walls than arteries

  - flows back to heart via muscle contractiond
• coronary arteries/veins (2)


  -supply heart with o2 and nutrients, removes waste and co2

  - coronary arteries branch off from aorta after left ventricle
• blood functions


  - transport (nutrients and gases)

  - regulated body temp

  - protects against infection
• blood components (4)


  - plasma (liquids)

  - red blood cells

  - white blood cells

  - platelets
• plasma (3)


  - fluid portion (matrix)

  - carries blood cells through vessels

  - pale transparent (90% water)
• plasma contains (6)


  electrolytes, proteins, nutrients, waste, cholesterol, hormones
• electrolytes (3)


  - dissolved inorganic salts

  - maintains osmotic pressure to prevent cell shrinkage or growth

  - adjusts water and electrolytes ratio
• proteins (2)


  antibodies - fights diseases, made by wbc

  fibrinogen - used in blood clotting
• nutrients


  - sugars, vitamins, amino acids, minerals

  - absorbed through villi in small intestine

  - carried by plasma to cells in body
• waste


  ammonia and urea to kidneys
• cholesterol


  builds hormones and outer cell membranes
• rbc functions (2)


  - erythrocytes

  - carries o2 from lungs to cells and co2 from cells to lungs

  - carries hemoglobin, increasing capacity of blood to carry o2 and co2
• rbc (4)


  - biconcave

  - 3 month lifespan

  - reproduces in bone marrow

  - lack a nucleus
• reproduction of rbc (4)


  - erythropoiesis

  - stem cells with nucleus; shrink and divide as they take up more hemoglobin; nucleus disappears (providing more volume); discharged to blood
• renal enthropoietic factor (2)


  - o2 levels decrease, kidneys release ref to stimulate RBC production

  - rate increases, can change based on high altitude, transfusions, or hemorrhaging
• anemia (2)


  - deficiency in hemoglobin (iron) or rbc

  - less o2 to tissues, less energy
• wbc


  - leukocytes

  - less numerous (1:700)

  - have a nucleus

  - different types have different functions

  - reproduces in bone marrow/lymphoid tissue

  - identified by shape and size of nucleus/cytoplasm granules
• phagocytes (3)


  - destroys invading germs by eating them using enzymes

  - eats dead cells

  - can leave circulatory system and wander through body
• lymphocytes (2)


  - creates antibodies to give immunities to disease

  - antibodies "tag" foreign antigens to be eaten by phagocytes
• platelets (4)


  - thrombocytes

  - cell fragments (irregular shape); no nucleus

  - made from large nucleated cells in bone marrow

  - blood clotting
• clotting process (4)


  damaged tissue releases thromboplastin

  prothrombin activates through clotting factors

  thrombin activated by prothrombin

  fibrin threads made by fibrinogen
• heartbeat (4)


  - cardiac cycle

  - atria contracts when ventricles are relaxed - lub

  (atrioventricular valves close - tricuspid, bicuspid)

  - ventricles contracts when atria relaxed - dupp

  (semilunar valves close - pulmonary, aortic)

  - sound caused by vibrations of heart when valves close
• diastole


  relaxation of heart muscle
• systole


  contraction of heart muscle
• sinoatrial (sa) node (5)


  - intrinsic

  - aka. pacemaker

  - found in upper back wall of right atrium

  - causes both atria to contract, initiates heartbeat

  - every .85s
• atrioventricular (av) node (3)


  - intrinsic

  - base of right atrium, near septum

  - recieves sa node pulse, causes ventricles to contract
• purkinje fibers (2)


  - takes av node pulse to the ventricles to cause contractions

  - ensures the contractions are synced; moves up like wave
• extrinsic control (3)


  - heart rate determined by nervous system

  - medulla oblongata can speed up/slow down heart rate from stimuli recieved

  - readjusts based on factors like stress, oxygen, and bp
• ecg (4)


  - recording of changes in myocardium during cardiac cycle

  - p wave: atria about to contract

  - qrs wave: ventricles about to contract

  - t wave: recovery of ventricular muscle
• myocardium


  muscle tissue in heart
• pulse


  expanding and recoiling of arterial wall that can be felt in any artery near surface of body

  eg: wrist pulse (radial), or neck pulse (carotid)
• blood pressure (3)


  - pressure of blood against wall of a vessel due to heart pumping

  - normal bp is 120/80 on arm

  - bp decreases with distance from left ventricle