Week 12: Neuron Structure and Function

The beginning of the axon, next to the cell body. This is where neuron signals are generated.

Axon Hillock

The branched end of the axon that makes contact with other cells. (this contact point is called a synapse)

Axon Terminal

coordinates sensory input and motor output

Diencephalon

Subdivision of diencephalon: involved with sleep/wake cycles- secretes melatonin

Epithalamus

Are changes in electrical charge at specific locations on the dendrites or neuron cells bodies.

Graded Potential

Subdivisions of the cerebellum.

Vestibulocerebellum Spinocerebellum Cerebrocerebellum

The cell itself- containing the nucleus and other organelles.

cell body

What part of a neuron receives incoming signals from other neurons?

dendrites

How does salutatory conduction increase the speed of nerve impulse conduction down an axon?

lets the action potential travel much faster down the axon than if it had to generate new potentials at every spot on the membrane

Subdivision of the brainstem: relays messages to and from the cerebellum

pons

What type of neuron transmits information about the internal and external environment of an organism and also sends information to the brain for processing?

sensory neurons

During this time, no new action potentials can be generated, no matter what the strength of the stimulus is.

Absolute Refractory Period

Subdivision of the diencephalon: -One of the main regulators of homeostasis -control, coordinate autonomic nervous system, endocrine system, involuntary muscle movements -Thirst and eating center regulation -Controls body temp. and circadian rhythms -controls endocrine (hormone) system along with the connected pituitary gland

Hypothalamus

The period of time when a stimulus of sufficient strength could cause an action potential.

Relative Refractory Period

Controls voluntary functions, like locomotion.

Somatic Nervous System

"fight or flight" functions

Sympathetic Division

Do nerve impulses travel faster or slower in large axons?

faster

What lobe of the cerebrum is involved in the conscious thought and motor function?

frontal lobe

coordinates and fine tunes muscle movements, maintains posture and balance, receives information about body position

Cerebellum

responsible for conscious thought, planning, sensory and motor processing

Cerebrum

How can a graded potential lead to an action potential?

If an electrical charge reaches the axon hillock an action potential is generated.

Subdivision of the brainstem: continuous with spinal cord, controls vital autonomic body functions

Medulla oblongata

Why are neurotransmitters needed to conduct nerve impulses, and how do they help conduct a nerve impulse?

Needed because it carries "signals" from the neuron to the receiving cells. Neurotransmitters are released into the synaptic cleft and they diffuse over, and bind to, receptors on the postsynaptic cell, The binding of the neurotransmitters to the postsynaptic cell opens ligand-gated ion channels in the membrane of that cell.

If a neurotransmitter hyperpolarizes a cell, how will that affect conduction of a nerve impulse (action potential)?

Neurotransmitters can either excite the postsynaptic cell which depolarizes the cell and causes an action potential to be generated. Or it inhibits the postsynaptic cell which hyperpolarizes the cell and makes it harder, or impossible, for an action potential to be generated.

"rest and digest" functions

Parasympathetic Division

What are the functions of cerebrospinal fluid?

Provides protection and an ideal chemical environment for the brain, the fluid acts as a cushion and allows the brain to float within the skull, the CSF has a special composition of just the right ions and nutrients to provide the neurons with an ideal environment for electrical function

Subdivision of the diencephalon: relays sensory information to cerebrum

Thalamus

Which division of the peripheral nervous system controls involuntary functions?

autonomic nervous system

Single long projection extending from the end of the cell body opposite the dendrites. Sends signals from the cell body to other cells.

axon

What are the two parts of the central nervous system of mammals?

brain and spinal cord

Refers to the concentration of sense organs at the anterior end of an organism's body.

cephalization

is made of neuron cell bodies and makes all of the decisions

gray matter

Mostly in the brain. Form connections between other neurons. Help analyze and interpret sensory data sent to the brain.

interneurons

What is white matter composed of?

made of myelinated axons and carry information between parts of the brain

Subdivision of the brainstem: processes sensory information

midbrain

Transmit signals from the brain to muscle or gland cells. Cause contraction of muscle or secretion of glands. Descending neurons.

motor neurons

Bundles of axons surrounded by connective tissue.

nerve

cells that send and receive information from throughout the body. (use electrical and chemical signals)

neurons

What lobe of the cerebrum is involved in processing visual information?

occipital lobe

What lobe of the cerebrum processes sensory information from the body?

parietal lobe

The period of time after an action potential when a new action potential can not be generated.

refractory period

What lobe of the cerebrum is involved in sound processing?

temporal lobe