Nervous System Anatomy

spinal cord

spinal cord

a long, thin, tubular bundle of nervous tissue and support cells that extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column

cerebellum

a major feature of the hindbrain responsible for body movements and balance

cerebrum

the principal and most anterior part of the brain in vertebrates, located in the front area of the skull and consisting of two hemispheres, left and right, separated by a fissure

midbrain

relays sensory and motor impulses; serves important functions in motor movement, particularly movements of the eye, and in auditory and visual processing.

pons

part of the brain stem, assists with regulation of breathing

medulla oblongata

part of brain stem, regulates heart rate, blood pressure, and breathing, and controls the reflexes of coughing, sneezing, and vomiting

hypothalamus

lower portion of diencephalon which acts as an autonomic center regulating metabolism, heart rate, blood pressure, thirst, hunger, energy level, and body temperature

thalamus

middle portion of diencephalon which relays sensory impulses up to the sensory cortex (aka the cerebrum); regulates sleep and consciousness

corpus callosum

a thick band of nerve fibers that divides the cerebral cortex lobes into left and right hemispheres and acts as the connection between the two.

meninges

three layers of protective tissue between the brain and skull

frontal lobe

cerebrum lobe responsible for memory, intelligence, behavior, emotions, motor function, and smell

occipital lobe

cerebrum lobe responsible for vision and speech

parietal lobe

lobe responsible for somatic sensations (pain, touch, temperature perception), and speech

temporal lobe

lobe responsible for hearing, smell, memory, speech, and emotion

brain stem

Portion of brain that contains the pons, medulla oblongata, and the beginning of the spinal cord, controls the flow of messages between the brain and the rest of the body, and it also controls basic body functions

Broca's area

area on left frontal lobe responsible for tongue and lip movements

primary motor cortex

area in frontal lobe responsible for sending impulses to muscles

primary somatic sensory cortex

area in parietal lobe responsible for interpreting sensory impulses from the body

dura mater

outermost meninges layer

sensory input

also known as the afferent pathway; the gathering information about changes in the environment

motor output

also known as the efferent pathway; the response sent from the CNS to the rest of the body

CNS

composed of brain and spinal cord

autonomic NS

involuntary control of cardiac and smooth muscles

Somatic NS

voluntary control of skeletal muscles

parasympathetic

part of autonomic N.S. responsible for "rest and digest" actions

sympathetic NS

part of the autonomic N.S. responsible for response to potential danger

neuroglia

neuron supporting cells of the nervous system

Astrocytes

neuroglia that protects neurons from harmful substances in the blood

ependymal

neuroglia that form a protective covering around the spinal cord and cavities of the brain

oligodendrocytes

neuroglia that produce myelin sheaths around nerve fibers in the CNS

Schwann cells

neuroglia that produce myelin sheaths around nerve fibers in the PNS

dendrites

conduct impulses toward the cell body of a neuron

axons

conduct impulses away from the cell body of a neuron

myelin sheath

insulating material on axon fibers that increase the rate of impulse transmission

neurotransmitter

a chemical messanger that sends a message from the axon terminals to a muscle or nearby neuron

synaptic cleft

a gap between axon terminals and nearby muscles or neurons

Nodes of Ranvier

areas on an axon without a myelin sheath; also known as gray matter

action potential

another name for a nerve impulse

depolarization

the inflow of sodium ions resulting in a more positive environment inside the neuron and the propagation of an action potential.

repolarization

the outflow of potassium ions resulting in the return of a more positive environment outside the neuron.

fissure

a deep grove in the brain

describe the major functions of the medulla...

carries out and regulates life sustaining functions that are done involuntarily (without thinking).

temporal lobe

responsible for processing auditory information from the ears

parietal lobe

processes sensory things that have to do with temperature, touch, and taste

frontal lobe

carries out higher mental processes such as thinking, decision making, and planning. (This is where our personality is formed

occipital lobe

responsible for processing visual information from the eyes. It helps you correctly understand what you are seeing

describe the major functions of the cerebral cortex

the cerebral cortex is where the four lobes are located

the cerebrum cortex is...

associated with higher brain function such as thought and action

what is a thalamus gland?

the thalamus serves as a relay station for impulses traveling to and from the spinal cord, brain stem, cerebellum, and cerebrum

describe the major functions of the cerebellum...

responsible for balance and coordination of muscles and the body. It is extremely important for being able to preform everyday voluntary things

Nervous system

Major communication system in the body. Functions in sensing, processing, communicating between the cells throughout the entire body

Central Nervous system

Consists of the brain and spinal cord

Peripheral nervous system

Consists of cranial and spinal nerves

Afferent pathway

Input. Away from the periphery to the CNS. Brain functions as the integrator. Includes somatic, special, and visceral senses

Efferent pathway

Output. Leaves the CNS and travels to the periphery. Includes somatic and automatic nervous systems and sympathetic and parasympathetic pathways

Neurons

Interconnect and communicate with each other. From the brain to spinal, to peripheral nerves, to the effector organs to allow us to react to our surroundings. Use electrical and chemical signals

Ventricles

Cavities filled with CSF, lined with ependymal cells

CSF

Secreted from support cells. Support the brain, regulate cell environment. Circulates through ventricular system. Produced by ependymal cells, supports/cushions against trauma, regulates environment of the brain

Astrocytes

Regulate extracellular environment (ions, neurotransmitters).

Microglia

Immune function (phagocytize bacteria and debris, release cytokines)

Oligodendrocytes

Myelinate central nerves multiple nerves at a time

Myelin

Protect axon from outside ions. Act like electrical tape. Made from schwann cells in the periphery and oligodendrocytes in the CNS

Ependymal cells

Secrete CSF, ions, proteins, etc. Line the ventricles

Dura mater

Thick/tough leathery sponge beneath the skull

Cerebrum

Most of the brain function. Higher level cognitive functions. Sensory integration, movement initiation, memory, emotion, consciousness

Brain stem

Autonomic funtions. Cardiovascular, respiratory control

Dendrites

Inpput- receive incoming signals. Multiple, short

Axons

Output- send signal "away." Single, long (up to 1M). Uniform diameter, often myelinated

Cerebrum Lobes

Four major lobes. Frontal, parietal, occipital, temportal

Occipital lobe

Primary visual cortex (sight)

Temporal lobe

Primary auditory cortex (hearing)

Frontal lobe

Primary motor cortex (voluntary movement)

Gyri

Bumps

Sulci

Grooves

Optic nerve

Vision

Thalamus

Relay center to/from cortex. All sensory information first stops at thalamus before proceeding to cortex. Multiple sub-nuclei "integrate" incoming sensory signals.

Hypothalamus

Maintains homeostasis by regulating metabolic processes (temperature, hunger, thirst, etc.)

Cerebellum

Coordinates motor output and regulates muscle tone. Compares intended movement coming from the motor cortex with actual movement sensation coming from the joints and muscles and makes corrections. Based on past experiences

Medulla Oblongata

Contains autonomic nuclei that control fundamental life processes required for human life. Respiration, heart rate, etc.