Genetics+and+Homeostasis

= = Each chromosome contains many (30,000) genes = = =﻿Homeostasis:=
 * __Genetics Review:__**
 * Four nitrogen bases: **Adenine, Cytosine, Guanine, Thymine**
 * Eukaryotic cells, DNA found in nucleus
 * **Example:** TAC CAT GAT ACA ATC à AUG GUA CUA UAG
 * **T à A, A à U, C à G, G à C**
 * Normal human body cells contain 46 chromosomes
 * Section of chromosome that codes for one protein is called a __gene__
 * Proteins determine traits
 * Proteins determine traits
 * Proteins determine traits

changing
 * __Homeostasis:__** Body’s ability to maintain relatively stable internal conditions even when the outside world is continuously
 * __Dynamic:__ within set limits/set point
 * __Outside Limits:__ homeostatic imbalance=disease/death
 * Requires all organ systems
 * Communication between organ systems is accomplished mainly by nervous and endocrine systems

-Face has more blood flow in cheeks than in your fingertips
 * Vascularity:** amount of blood vessels in a particular area
 * Vasoconstriction:** gets smaller (when you’re cold)
 * Vasodilation:** gets bigger (when you’re hot) the blood vessels expand, allowing more flow
 * Adrenaline:** dilator
 * Hyperthermia:** red appearance (DOES NOT go pale)

What Happens on a Hot Day: blood vessels of **skin dilate** increasing the flow of warm blood to the skin. More heat is now lost because blood cools as it cases near the surface of the skin. Sweat glands secrete more sweat and as this evaporates from skin it carries heat away from the body.

What Happens on a Cold Day: blood vessels of **skin constrict**. This decreases flow of warm blood near body surface so it reduces heat loss and keeps internal structures warm. Muscles of body hairs will contract making hair stand upright, if there’s no hair, you will see goose bumps.