cells and tissues Flashcards
homeostasis
a state of balance among all the body systems needed for body to survive and function correctly
How is homeostasis achieved in the maintenance of blood calcium
body achieves homeostasis through negative and positive feedback loops to decrease of increase the reaction.
explain a negative feedback loop and example
receptor - picks up stim - control centre - decision made - effector
e.g thermoregulation
receptors in skin - detect increase in body temp - info sent to hypothalamus - info relayed to blood vessels - effector = vasodilation
explain a positive feedback loop and example
amplifies change, does not maintain balance. body’s reaction to change e.g. body temp increasing to fever
can create a harmful positive loop e.g shivering and sweating or beneficial - lactation or platelet helping cuts
name 4 types of tissue
epethelial, connective, nervous and muscular
definition of nucleus
contains DNA, blue print for proteins
definition of nucleolus
production of ribosome
defintion of ribosome
manafactures proteins
definition of rough ER (endoplasmic reticulum)
studded with mature ribosomes (protein factory)
definition smooth ER (endoplasmic reticulum)
lipid synthesis/detoxification
definition of golgi apparatus
processing and packaging proteins
definition of mitochondria
energy and heat production
defintion of lysosome
destruction of debris and waste products
definition of lysoskeleton
structural support and internal organisation
describe the structure of the cell membrane
it is a plasma membrane, the part that closes up the cell. A thin flexible barrier that regulates movement of substances.
Made up of phospholipids (fatty molecules) that have a phosphate head group and then the fatty acid tail. They line up/arrange themselves to create a structure - ‘bilipid layer’ so charged particles cannot get through and impermeable for most water soluble molecules.
