circulatory system Flashcards
homeostasis
the body’s maintenance of a relatively stable internal physiological environment
negative feedback loop
process that reverses deviation from normal body constant
sensory rececptors -> integrator -> effector
positive feedback loop
exacerbates/perpetuates small disturbances
veins
blood vessels that return blood to the heart
thinner, more elastic walls + larger lumens due to lower blood pressure
valves prevent the backflow of blood
arteries
blood vessels that carry blood from the heart to body tissues
thicker, elastic walls due to higher blood pressure
made of connective, smooth muscle and epithelial tissues
capillaries
blood vessels that connect arteries and veins
tiny, one cell thick walls to allow for gas exchange and diffusion
the heart
driving force and pump of the circulatory system
4 chambers (right + left atrium, right + left ventricle)
septum prevents blood from mixing
aortic + pulmonary semilunar, tricuspid and biscupid valves
pathway of blood
body tissues -> superior vena cava -> right atrium -> tricuspid valve -> right ventricle -> pulmonary semi-lunar valve -> pulmonary arties -> lungs -> pulmonary arterioles -> capillaries -> pulmonary venuoles -> pulmonary veins -> left atrium -> bicuspid valve -> left ventricle
components of the blood
plasma
erythrocyte (rbc)
leukocyte (wbc)
platelets
erythrocytes (rbc)
44% of blood volume produced in bone marrow life span 120 days no nucleus contains hemoglobin
leukocytes (wbc)
1% of blood volume
produced in bone marrow (spleen, tonsils)
can double in volume during infection
nucleus
macrophages
big eaters
lives a few days
phagocytic, can cross capillary walls
generalized response to infection
lymphocytes
unknown life span
non-phagocytic
acquired, specific immune response
systemic circulation
carries oxygenated blood to the body tissues and deoxygenated blood back
pulmonary circulation
carries deoxygenated blood to the lungs and oxygenated blood back
hypertension (high blood pressure)
condition caused by increased volume/rate of blood or reduced elasticity in the artery
symptom: nosebleeds
cause: diet high in salt
tx: diet lower in salt
atherosclerosis
narrowing of arteries due to deposits of cholesterol-rich plaque on the innermost layer of the artery
symptom: heart attack
cause: HDL levels too low
tx: diet lower in saturated fats and higher in fruits and vegetables
arteriosclerosis
narrowing of arteries due to deposits of cholesterol-rich plaque underneath the inner layer of the artery
symptom: stroke
cause: years of plaque build-up
tx: coronary bypass surgery
stroke
an embolism reaches the brain, blocking the brain from receiving oxygenated blood, the brain cannot receive oxygen
symptom: drooping face (FAST)
cause: arteriosclerosis
tx: thrombolytic medication
heart attack
the flow of oxygenated blood to the heart becomes blocked, heart cannot receive oxygen
symptom: pressure in arms, neck, jaw and back
cause: atherosclerosis
tx: aspirin
how a heart beats
SA node sends signal ->right atrium fills with blood AV node sends signal ->tri/biscupid valves open signal transfers to bundle of His signal goes to purkinje fibres, to each side of the ventricle ->heart pumps ->bloods is moved out of the heart
SA node
bundle of specialized muscle tissue that stimulates the muscle cells to contract and relax rhythmically by generating a signal that spreads across the heart
AV node
bundle of specialized muscle tissue that receives the electrical signal and transmits them through the bundle of His
bundle of His
bundle of specialized fibres that relays the electrical signal to the Purkinje fibres
