chapter 12 anatomy study guide

How do the nervous and endocrine systems work together?

The nervous system sends fast messages using electrical signals, while the endocrine system sends hormones through the blood. Together, they help control body functions and keep the body balanced.

What are the three main functions of the nervous system?

Sensory input: Detects changes inside and outside the body.

Integration: Processes and interprets information.

Motor output: Sends commands to muscles and glands.

What is sensory input?

Sensory input is when the nervous system receives information from the body or the environment, such as heat, pain, sound, or light.

What are afferent neurons?

Afferent neurons carry sensory information from receptors toward the central nervous system (CNS).

What is integration?

Integration is when the nervous system processes information and decides how the body should respond.

What are interneurons?

Interneurons connect neurons and help process information. Most are located in the CNS.

What is motor output?

Motor output is when the nervous system sends commands to muscles or glands to create a response.

What are efferent neurons?

Efferent neurons carry commands away from the CNS to muscles and glands.

What is the difference between afferent and efferent neurons?

Afferent neurons carry information toward the CNS, while efferent neurons carry commands away from the CNS

What is an example of sensory input, integration, and motor output?

If you touch a hot stove, sensory neurons detect the heat, the nervous system processes the information, and motor neurons tell your muscles to pull your hand away.

Why are the three functions of the nervous system important?

They allow the body to sense changes, understand information, and respond to situations.

What is the central nervous system (CNS)?

The CNS consists of the brain and spinal cord.

What is the peripheral nervous system (PNS)?

The PNS includes all the nerves and nervous tissue outside the brain and spinal cord.

What is the main function of the CNS?

The CNS processes information, makes decisions, and controls the body's responses.

What is the main function of the PNS?

The PNS carries information between the CNS and the rest of the body.

What is the difference between the CNS and PNS?

The CNS is the brain and spinal cord, while the PNS connects the CNS to the rest of the body.

What are the three main physiological properties of neurons?

• Excitability

• Conductivity

• Secretion

What is excitability?

Excitability is a neuron's ability to respond to a stimulus, such as a chemical or a change in temperature.

What is conductivity?

Conductivity is a neuron's ability to transmit an electrical signal along its membrane.

What is secretion in neurons?

Secretion is when a neuron releases chemical messengers called neurotransmitters to communicate with another cell.

What is a neuron?

A neuron is a specialized nerve cell that receives and sends information throughout the body.

What is the soma?

The soma, or cell body, contains the nucleus and most of the organelles. It keeps the neuron functioning.

What are dendrites?

The soma, or cell body, contains the nucleus and most of the organelles. It keeps the neuron functioning.

What is the axon?

The axon is a long extension that carries electrical signals away from the cell body.

What is the axon hillock?

The axon hillock is the area where the axon begins. It helps determine whether the neuron will generate an electrical signal called an action potential.

What is the myelin sheath?

The myelin sheath is a fatty covering around some axons that helps electrical signals travel faster.

What is a node of Ranvier?

A node of Ranvier is a small gap between sections of myelin along an axon.

What is an internode?

An internode is a section of an axon covered by myelin between two nodes of Ranvier.

What is an axon terminal?

The axon terminal is the end of an axon that releases neurotransmitters to communicate with another cell.

How do the parts of a neuron work together?

Dendrites receive signals, the soma processes them, and the axon carries an electrical signal toward the axon terminals. The terminals release neurotransmitters to pass the message to another cell.

Why do neurons have different shapes and sizes?

Neurons have different shapes and sizes because they perform different jobs and connect with different parts of the body.

What are the three common structural types of neurons?

• Multipolar: Have many dendrites and one axon.

• Bipolar: Have one dendrite and one axon.

• Unipolar (pseudounipolar): Have one main extension that branches into two parts.

What are the functions of these neuron types?

Multipolar neurons are common in the brain and spinal cord and include many motor neurons. Bipolar neurons are found in certain sensory organs, such as the retina. Unipolar neurons commonly carry sensory information, such as touch and pain.

What are neuroglia?

Neuroglia, also called glial cells, are cells that support, protect, and maintain neurons.

What are the four main types of glial cells in the CNS?

• Astrocytes

• Oligodendrocytes

• Microglia

• Ependymal cells

What do astrocytes do?

Astrocytes support neurons, help maintain the chemical environment around them, and help regulate the blood-brain barrier.

What do oligodendrocytes do?

Oligodendrocytes produce the myelin sheath around axons in the CNS.

What do microglia do? Microglia protect the CNS by removing germs, damaged cells, and cellular waste.

Microglia protect the CNS by removing germs, damaged cells, and cellular waste.

What do ependymal cells do?

Ependymal cells line the brain's ventricles and the spinal cord's central canal. Some help produce and circulate cerebrospinal fluid.

What are the two main types of glial cells in the PNS?

• Schwann cells

• Satellite cells

What do Schwann cells do?

Schwann cells produce myelin around axons in the PNS and help support nerve repair.

What do satellite cells do?

Satellite cells surround neuron cell bodies in PNS ganglia and help regulate their surrounding environment.

What is the function of myelin?

Myelin insulates axons and helps electrical signals travel faster and more efficiently.

How does myelin increase the speed of nerve signals?

Myelin allows the electrical signal to travel from one node of Ranvier to the next. This is called saltatory conduction.

Which cells produce myelin in the CNS?

Oligodendrocytes produce myelin in the CNS.

Which cells produce myelin in the PNS?

Schwann cells produce myelin in the PNS.

What is the difference between oligodendrocytes and Schwann cells?

Oligodendrocytes produce myelin in the brain and spinal cord. Schwann cells produce myelin in peripheral nerves. One oligodendrocyte can myelinate parts of multiple axons, while each myelinating Schwann cell covers one segment of one axon.

What happens if myelin is damaged?

Electrical signals may slow down or fail to reach their destination. This can cause problems with movement, sensation, balance, or other nervous system functions. For example, multiple sclerosis damages myelin in the CNS.