CORE BIOLOGY

THE NERVOUS SYSTEM

The nervous system consists of two parts: conscious part:the brain

unconscious: the spinal cord The stimuli (change in human environment) requires immediate response. This is generated either by the brain or the spinal cord.

The distance from stimuli to spinal cord is activated by Reflex Arc. The electrical signals from a stimuli travel along the synapses as chemicals and are released into the gap. The two types of neurones involved in the process are: motor and sensory

5 Sense organs and stimuli

eyes- vision tongue- taste ears(the sensitive hairs cochlea)

nose- distinct smells skin-pressure and touch

tongue- taste

skin-touch, pressure

Homeostasis- the maintenance of constatnt internal environment within a human body

3 main things to control:

ion content

sugar levels

water content

ion content is controlled- by the kidneys

sugar levels by the hormone insulin (that is secreted by organ - pancreas)

water content by the ADH secreted by the pituitary gland controls (the osmoregulation) in human body

METABOLISM-

The rate at which the chemical reactions(digestion and the energy release from nutrients) within a human body occur

High Metabolic Rate:

Men tend to have higher metabolic rate because they have bigger proportion of muscles to women

People who have excess weight because the energy demand is big

Athletes and those who do more strenuous work.