Endocrine System, Nervous System and Homeostatic Control

Endocrine system

Information signaling system

Glands produce hormones

Circulate through blood vessels

Regulate:– mood,

growth and development, tissue function, and metabolism

Hypothalamus

The hypothalamus controls body temperature, hunger, thirst, fatigue, anger, and circadian cycles.

Secretes hormones that tell other glands to create their hormones

– GHRH

Pineal Body

Secretes Melatonin Melatonin may help

regulate sleep patterns

Pituitary Gland

Growth Blood Pressure Sex Organ Functions Conversion of food into

energy Water regulation

Thyroid

Controls how quickly the body burns energy, makes proteins, and how sensitive the body should be to other hormones.

Parathyroid

The sole function of the parathyroid glands is to maintain the body's calcium level within a very narrow range.

Pancreas

Regulates blood sugar by producing Insulin

Adrenal gland

Produces Adrenaline Fight or Flight

Response– Dilate pupils– Increase heart rate– Suppress non

emergency process– Boost oxygen and

glucose supply

Testes and Ovaries

Both produce hormones to support body function

Testes– Testosterone

Ovaries– Progesterone– Estrogens

Nervous system

Made up of two major parts

– Central Nervous System (CNS)

– Peripheral Nervous System (PNS)

Neurons

Central Nervous System

Brain and Spinal Cord– Nerves– Ganglion

Brain

Consists of lobes, Each lobe having different functions.

Function

Process information Dictate reactions and behaviors

Peripheral Nervous system

Nerves from spinal cord to rest of body Create locomotion Etc…

Feedback Loops

Your nervous system is involved in almost all homeostatic control loops.

Reflex arc Sensory Vs Motor Affector Vs Effector

Neuron Function

Dendrites Myelin Schwann Cells Axon Node of Ranvier

Threshold

Before a neuron can send out a signal the stimuli has to pass the threshold

Action Potential

An action potential is a nerve impulse

An electrical shock sent down the axon

Action Potential

Synapse

A synapse occurs where ever the action potential meets the end of the axon

It needs to propagate across that gap

It does this through chemical messengers

Neurotransmitter= Acetylcholine

Enzyme that destroys it = Acetylcholinesterase

Synapse

When Acetylcholine jumps across the gap, it tells the next neuron to fire it’s action potential and the process continues

Homeostasis Summary

Homeostasis is the maintenance of a stable internal state within an organism.

Organisms must respond and maintain homeostasis in relation to many factors.

Organisms detect changes in their environment and respond to these changes in a variety of ways.   

These changes may occur at the cellular or organism level.