Homeostasis study

Homeostasis

The regulation and maintenance of the internal environment. Work hard to stabilize the environment inside your body.

Necessary for normal body functioning and to sustain life.

Examples of homeostasis

sweating and shivering

Sweating

When your body is hot, sweat glands are stimulated to release sweat.

shivering

response to cold; body shakes to turn energy from food into body heat

Muscles start to contract and release to maintain energy and heat.

vasodilation

A widening of the diameter of a blood vessel.

The capillaries under your skin will get filled with blood if you get too hot.

How to control blood glucose levels

If the levels are too high, the pancreas will sense something off and secrete insulin into the liver, this gets converted to glycogen.

If the levels are too low, the pancreas secretes more glucagon, which converts to glycogen.

Stimulus

Change in internal or external environment

Receptors

detects stimulus and sends information to the control center

Control center

Most commonly the brain. Compares information from receptors to the conditions that are bet for you body.

Effectors

Initiates response in target cells.

negative feedback

a mechanism of response in which a stimulus initiates reactions that reduce the stimulus

Examples: sweating, shivering, blood pressure control, and secreting insulin and glucagon for blood glucose control

Positive feedback

A type of regulation that responds to a change in conditions by initiating responses that will amplify the change. Takes organisms away from a steady state.

Example: getting a fever and giving birth

sensory neurons

have specialized receptor ends that sense stimuli and then carry impulses from peripheral body parts to the brain or spinal cord

Interneurons

lie entirely within the brain and spinal cord: direct incoming sensory impulses to appropriate parts of the body for processing and interpreting

Motor Neurons

carry impulses out of the brain or spinal cord to muscles and sweat glands(effectors)

The central nervous system(CNS)

is composed of the brain and spinal cord. These neurons cannot regenerate if damaged

The peripheral nervous system (PNS)

Is made up of peripheral nerves that connect the CNS to the rest of the body. These neurons can regenerate if damaged.

autonomic nervous system

Cranial and Spinal nerves connecting CNS to heart, stomach, intestines, glands

Controls unconscious activities.

somatic nervous system

Cranial and spinal nerves connect the CNS to skin and skeletal muscles.

Oversees conscious activities

parasymoathetic nervous system

Decreases heart rate, bronchodilation, blood glucose, and blood to skeletal muscles.

Increases digestion, pupil size, urinary output.

"Rest and Digest"

Sympathetic nervous system

Decreases digestion, pupil size, and urinary output

Increases heart rate, bronchodilation, blood glucose, and blood to skeletal muscles

"Fight or flight"

Nervous tissues

composed of two major cell types: Neurons and neuroglial cells.

Nerves

are cable- like bundles of axons

neuroglial cells

provide physical support, insulation, and nutrients for neurons.

Neurons

a nerve cell; the basic building block of the nervous system

Dendrites

branches of the cell that extend out to receive messages from other cells.

Axons

a long branch that transmits messages to other cells

Synapse

A tiny gap between the neurons that the message travels between.

membrane potential

the voltage difference across a membrane

resting potential

the voltage across the plasma membrane of a resting neuron.

Action potential

a massive change in membrane voltage that transmits a nerve signal along an axon

Functions of the ciculatory system

Transports gases and hormones, removes wastes.

Contains white blood cells

Helps to maintain homeostasis

Arteries

the largest blood vessels, they carry blood away from th heart to the rest of the body

Veins

the second largest blood vessels, they carry blood from the rest of the body back to the heart

Capillaries

the smallest blood vessels, they carry blood to and from the body's cells. They are so thin that nutrients and gases can diffuse right through them.

They exchange substances between the blood and interstitial fluid tissues.

Interstitial fluid

fluid in the spaces between cells

White blood cells

fights infections

Red blood cells

carries oxygen to cells and carbon dioxide out

Platelets

Clots blood to stop bleeding