topic 11 chapter review

(11.1) distinguish between an antibody and an antigen and explain how vaccination provides protection against diseases

antigen - a fragment of a foreign pathogen presented on the surface of an infected cell or macrophage. antibody - a protein produced by B cells, each specific to a particular antigen that it targets. vaccination provides a weakened or dead pathogen to induce an artificial active acquired immunity where, although the pathogen is artificially injected, the body produces its own antibodies. this helps B cells divide and produce memory cells which will allow the body to produce a quicker and stronger immunological response when re-exposed to the disease. herd immunity alsoprotects those who are not vaccinated because the disease is very unlikely to circulate.

(11.2) describe the role of the musculoskeletal system in movement

the skeleton gives muscles a rigid attachment point. joints (the meeting point of two bones by cartilage and occasionally sunovial fluid) allow for movement. muscles work together, taking on different roles. agonistic muscles are the primary muscles responsible for movement. antagonistic muscles produce the opposite effect to agonistic muscles (if agonistic muscles contract, antagonistic ones extend), allowing for back and forth, controlled movements. synergists assist the agonists by fine-tuning the movement. parts of the body may move in one-three planes based on the type of joint. hip joints have a ball-and-socket mechanism (three planes/free movement). elbows have a hinge joint (one plane/back and forth).

(11.3) how does the structure of the kidney relate to its role in excretion and osmoregulation?

the kidney is comprised of parts like the outer cortex, the inner medulla, renal pelvis, renal vein and artery, and the ureter. each kidney has about a million nephrons lining the cortex and medulla. nephrons are components which filter the blood for secretion and reabsorption. the globulus and bowman’s capsule form the initial filtrate. then, the proximal convoluted tubule reabsorbs glucose, amino acids, salts. the loop of henle reabsorbs some water and salts, depending on the salt gradient in the medulla, and therefore the body’s need for water. the distal tubule continues to fine-tune the filtrate coming from the loop of henle. the final filtrate, urine, goes down the collecting duct, which may reabsorb some of the urine for the salt gradient. the urine travels to the renal pelvis, then through the ureter, stored in bladder, and excreted by the urethra.

(11.4) explain the role of hormones infertilisation and embryonic development.

once an egg is fertilised and an embryo starts developing, it secretes HCG, which maintains the corpus luteum from degeneration. it is needed for secretion of progesterone and estrogen, which the placenta can not do until it develops at around 3 months into the pregnancy. progesterone inhibits uterine contraction, estrogen prepares mammary glands for lactation and high levels of it induce labor, while both maintain the endometrium. oxytocin stimulates contractions, and prolactin maintains milk secretion.