BIOL 1080 Study Guide - Final Guide: Natural Killer Cell, Mitral Valve, Heart Valve
Document Summary
Negative feedback: i. e. pancreas responds to high levels of blood u. by releasing insulin > continues until set-point is reached. Positive feedback: i. e. during childbirth, oxytocin is released to stimulate contractions of the uterus, contractions then stimulate release of more oxytocin, goes on and on. Pituitary gland: secretes adh, gh, tsh, acth, fsh, lh. Pineal gland: tiny gland at the centre of the brain, secretes melatonin=> higher levels at night, lower during day, in uences daily rhythms. Seasonal affective disorder (sad): too much melatonin, lethargy, low spirits, craving carbs. Skin: provides a physical barrier to the entrance of microbes. Mucus membranes: mucus traps organisms, cilia sweep away trapped organisms. Skin: skin has a lower ph in order to make it dif cult for the growth of organisms, sweat and oil secretions kill many bacteria. Stomach: hydrochloric acid kills many bacterium in stomach vagina: bene cial bacteria that create an acidic environment that discourages growth of pathogens.
