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.