29.1 how organ systems communicate qq 4/14/08 draw and label a nerve cell include: cell body,...

29.1 How Organ Systems Communicate

QQ 4/14/08 Draw and label a nerve cell include: cell body, dendrite, axon, schwann cell, terminal, synapse.


KEY CONCEPT How do the organ systems communicate?

By the Nervous System and Endocrine System


Communication systems = maintain homeostasis.

• A stimulus causes a response.– Responses can be chemical, cellular, or behavioral. – The nervous and endocrine systems respond to stimuli.


• The nervous system controls thoughts, movement, and motion.

• This happens quickly

• The endocrine system controls growth, development, and digestion.

• This happens more slowly


The nervous and endocrine systems have different methods and rates of communication.

• The nervous system works quickly, using chemical and electrical signals.

spinal chord

nerves

– interconnected network of cells– signals move through cells – divided into central nervous system (CNS) and peripheral nervous system (PNS)


• The endocrine system works more slowly.

– only chemical signals– signals move through bloodstream – physically unconnected organs

receptor

target cell

not a target cell

bloodstream

hormone


KEY CONCEPT Nervous System - made of highly specialized cells.


Neurons are highly specialized cells.

• A neuron has three parts.– cell body has nucleus and organelles

1 Cell body


– dendrites receive impulses



2 dendrites


– axon carries impulses

3 axon

– dendrites receive impulses




• Neurons have other structures to transmit signals.

– Schwann cell


– synapse

synapse


– Schwann cell


– terminal

– synapse


– Schwann cell

axon terminal


Neurons receive and transmit signals.

• Resting potential means no signal is being transmitted. – more Na+ outside of cell – more K+ inside of cell


• An action potential is a moving electrical impulse.

– It is generated by a stimulus.– Na+ enters, and cell becomes

positively charged.– K+ leaves, and area of positive

charge moves.

area of detail


• A chemical signal passes between neurons.

– Impulse reaches terminal.

impulse



– Impulse reaches terminal.

synapse

receptorvesicles

impulse

neurotransmitter

– Neurotransmitters released into synapse.



– Impulse reaches terminal.– Neurotransmitters released into synapse.

impulse

synapse

receptorvesicles

neurotransmitter

– Neurotransmitters stimulate next cell.


KEY CONCEPT The senses detect the internal and external environments.


The senses help to maintain homeostasis.

• Senses gather stimuli, and send it to the nervous system.

• Nervous system responds to stimuli.– Pupils shrink when too much

light enters the eyes.– Goose bumps when cold air

touches skin.


The senses detect physical and chemical stimuli.

• The eye is for vision. – Special cells collect light

information (rod and cone cells)

– Send information to brain in the optic nerve (a bunch of neurons)


• The ear is for to hearing.

– Special hair cells in inner ear.– Bend with sound, each hair cell is attached to a neuron

that sends the information to the brain


• Taste and smell use chemoreceptors.

– Special cells in nose and mouth that are sensitive to chemicals

– Attached to neurons that send the information to the brain


• The skin senses touch.– Special cells to detect three things

– Pressure / touch– Pain– Temperature

pain receptor

light pressure receptor

hair follicle

heavy pressure receptor


• The spinal cord controls reflexes.

– sensory neuron sends information to spinal cord– spinal cord directs information to motor neuron – does not involve the brain

interneuron

motor neurons

sensory neuron


The PNS links the CNS to muscles and other organs.

• The somatic nervous system regulates voluntary movements.

• The autonomic nervous system controls involuntary, functions

– sympathetic nervous system: “fight vs. flight”

– parasympathetic nervous system: calms the body, conserves energy


KEY CONCEPT The endocrine system produces hormones that affect growth, development, and homeostasis.


Hormones influence a cell’s activities by entering the cell or binding to its membrane.

• Glands are organs of the endocrine system.


• Hormones are chemical signals that influence cell’s activities.– produced by glands– travel through the circulatory system– affects cells with matching receptors

target cell

hormone

receptornot a target cell

bloodstream


Endocrine glands secrete hormones that act throughout the body.

• There are many glands located throughout the body.

– Hormones travel through the bloodstream to cells with matching receptors.

HYPOTHALAMUS

PITUITARY

THYROID

THYMUS

ADRENAL GLANDSPANCREASFEMALE GONADS :OVARIES

MALE GONADS : TESTES


The hypothalamus interacts with the nervous and endocrine systems.

– a structure of both the nervous andendocrine systems

– produces releasing hormones,sent to pituitary gland

• The pituitary gland is found below the hypothalamus in the brain.– controls growth and water

levels in blood – produces releasing hormones

sent throughout the body

• The hypothalamus is a gland found in the brain.


• Releasing hormones stimulate other glands to produce hormones.– allow glands to

communicate with one another

– are used in temperature regulation

29.1 how organ systems communicate qq 4/14/08 draw and label a nerve cell include: cell body,...

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