1. Nervous and Endocrine System
Human Body Systems
Nervous and Endocrine System

2. The nervous system and the endocrine system provide the means by which organ systems communicate.
The body’s communication systems help 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 emotion.
The endocrine system controls growth, development, and digestion.

3. The nervous and endocrine systems have different methods and rates of communication
The nervous system works quickly, using chemical and electrical signals.
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

4. Neurons are highly specialized cells.
A neuron has three parts.
cell body has nucleus and organelles
dendrites receive impulses
axon carries impulses
Neurons have other structures to transmit signals.
Schwann cell
synapse
terminal

5. 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.

6. A chemical signal passes between neurons
Impulse reaches terminal
Neurotransmitters released into synapse.
Neurotransmitters stimulate next cell
Crash

7. Senses 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.

8. Sight The senses detect physical and chemical stimuli.
The eye contributes to vision.
Photoreceptors sense light.
Two photoreceptors work together: rod cells and cone cells.
Bristol

9. The ear contributes to hearing.
mechanoreceptors called hair cells
bend in response to vibrations
How it works

10. How do we taste? Taste and smell use chemoreceptors
Taste uses tongue, and smell uses nose.
Chemoreceptors detect chemicals dissolved in fluid.

11. Touch The skin senses touch with Meissner’s corpuscle.
Pacinian corpuscle detect pressure.
Nociceptor detect pain and damaged tissue
Thermoreceptors detect temperature

12. The central nervous system interprets information, and the peripheral nervous system gathers and transmits information.
The nervous system’s two parts work together.
The Central Nervous System (CNS) includes the brain, brain stem, and spinal cord.
The Peripheral Nervous System (PNS) includes four systems of nerves.

13. The CNS and PNS pass signals between one another
Sensory receptor generates impulse.
PNS passes impulse to CNS.
CNS interprets impulse.
CNS passes impulse to PNS.
PNS stimulates a response.

14. The Brain has Three Parts
Cerebrum (forebrain) controls thought, movement, emotion
Cerebellum (hindbrain) allows for balance
brain stem (midbrain) controls basic life functions
Bristol

15. The brain stem has three parts
midbrain controls some reflexes
pons regulates breathing
medulla oblongata controls heart function, swallowing, coughing

16. The spinal cord controls reflexes
sensory neuron sends impulse to spinal cord
spinal cord directs impulse to motor neuron
does not involve the brain

17. The PNS links the CNS to parts of the body
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

18. Scientists study the functions and chemistry of the brain
Today, scientists study the brain without surgery
There are three common technologies
CT uses x-rays to view structure
MRI uses magnetic fields and radio waves to view structure
PET detects activity, where glucose is used, in the brain

19. Changes in brain chemistry can cause illness
Different neurotransmitters relate to different functions
some stimulate impulses
some prevent impulses
Abnormal levels of neurotransmitter can cause illness
schizophrenia
depression

20. Drugs alter brain chemistry
Addiction is the physiological need for a substance.
Tolerance occurs when more drug is needed to produce an effect.
Drugs might cause desensitization or sensitization.
desensitization: more neurotransmitter leads to fewer receptors
sensitization: less neurotransmitter leads to more receptors.

21. Stimulants cause more action potentials
may increase neurotransmitter in synapse
may decrease removal of neurotransmitter in synapse

22. Depressants cause fewer action potentials
may produce neurotransmitter that prevent impulses
may slow release of neurotransmitter that generates impulses

23. 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.
There are many glands located throughout the body.
Hormones travel through the bloodstream to cells with matching receptors.

24. Hormones are chemical signals that influence cell’s activities
produced by glands
travel through the circulatory system
affects cells with matching receptors
There are steroid hormones and nonsteroid hormones
Steroid hormones enter the cell.
Nonsteroid hormones do not enter the cell

25. The hypothalamus interacts with the nervous and endocrine systems
The hypothalamus is a gland found in the brain
a structure of both the nervous and endocrine 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

26. Hormones Conclusion
Releasing hormones stimulate other glands to produce hormones
allow glands to communicate with one another
are used in temperature regulation
Hormonal imbalances might be treated with surgery or medicine.
Steroids, a pituitary tumor, or some prescription drugs can make the pituitary overactive and indirectly cause problems.
Summary