Chapter 29 Review

Section 29.1

• The nervous system (brain, spine, nerves) and endocrine systems (glands that produce hormones) allow for communication inside the body

• These systems respond to a stimulus- something that causes a response or change in the animal (e.g. sight, sound, smell, etc.)

Differences between the communication systems

• Nervous system responds quickly and has short-term effects.

• Endocrine system responds more slowly and has long-term effects.

• Nervous system controls thoughts, movements, and emotions.

• Endocrine system controls growth, development, and response to the environment.

The Nervous System

• Divided into 2 parts: • Central Nervous System(CNS)- brain and spinal

cord • Peripheral Nervous System(PNS)- network of

nerves spread throughout the body (everywhere except brain and spinal cord).

• PNS sends signals to CNS, which CNS processes, then sends signal back to PNS to tell the body what to do.

Section 29.2

• Neurons: cells that make up the nervous system.

• Neurons store information and send signals to the brain and throughout the body.

• Neurons have 3 parts: dendrites (branch-like area at front of neuron), cell body (has nucleus), and axon (long tail end of neuron)

Movement of Signals Inside a Neuron

• Resting potential is when the neuron is not active. The inside of the neuron is negative, while the outside is positive.

• A signal is picked up by the dendrites of the neuron, then passes through the cell body and goes down the axon until it reaches the axon terminal.

• The signal (or impulse) that goes through the neuron is called an action potential.

• In an action potential, the inside of the neuron becomes positive while the outside is negative (because sodium moves into the neuron).

Neurotransmitters

• When the action potential reaches the axon terminals (end of axon), it causes vesicles to release chemical messengers (neurotransmitters) into the synapse (the gap between two neurons).

• The neurotransmitter goes through the gap and binds to receptors on the other neuron. This moves the signal (action potential) from the first neuron to the second neuron.

Section 29.4

• CNS-brain and spinal cord-processes information that comes from the rest of the body (the PNS).

• CNS has interneurons that interact with other nerves in the body.

• PNS sends signals from the body (e.g. muscles, organs) to the CNS and then responds to signal from the CNS.

• PNS has sensory neurons (detect stimuli) and motor neurons (control muscles).

Peripheral Nervous System

• PNS is divided into somatic nervous system (controls voluntary muscles) and autonomic nervous system (controls involuntary muscles).

• Somatic nervous system is used when you raise your hand.

• Autonomic nervous system is used when you are breathing.

Autonomic Nervous System

• This is divided into 2 parts:

• Sympathetic nervous system-controls fight or flight response.

• Parasympathetic nervous sytem-calms the body down after fight or flight response.

Section 29.5

• Changes in the brain can cause illness. • If there are too many or too few

neurotransmitters, that can hurt the function of the brain.

• Illnesses of the brain include schizophrenia and depression.

• Brain can become dependent on a drug (addiction), such that larger doses of the drug are needed to cause a response (tolerance).

Section 29.6

• The Endocrine System is made of glands that produce hormones.

• Hormones are chemical messengers that enter the blood and travel through the body.

• Hormones bind to receptors on target cells to cause a response in the cell.

Control of Hormones

• The hypothalamus (small region inside the brain) is the master regulator of the endocrine system.

• Hypothalamus sends releasing hormones to the pituitary gland.

• The pituitary gland releases its own hormones as a response.

• The hormones from the pituitary causes glands like the pancreas to produce hormones (e.g. insulin).

• When hormone levels are too high, the hormones cause the hypothalamus to stop sending its releasing hormones. This is called negative feedback.