Unit 4 Communication and Coordination (Nervous System)

3 basic functions of the nervous system

a. Detects changes (stimuli) in the internal or external environment

b. Evaluates the information detected

c. Can respond by initiating changes in muscles or glands

central nervous system vs peripheral nervous system

CNS – Central nervous system

Brain & Spinal Cord

Controls & Coordinates all communication within the body.

PNS – Peripheral nervous system

All neurons extending beyond the brain and spinal cord

A communications network extending to all parts of the body.

neuroglia

GLIA or GLIAL CELLS - do not usually conduct information but support the function of

neurons structurally & metabolically

Schwann cells

Cells that produce myelin - they are located within the myelin sheath ( axon).

difference between gray matter and white matter

White matter: Made up of myelinated axons and responsible for learning/cognition

Gray matter: made up of neutrophils, glial cells, neuronal cell bodies, capillaries, synapses,

and a few myelinated axon. Responsible for sensory perception, muscle control, self-control,

decision-making, memory, and data processing

nerves

Excitable cells that conduct chemical-electrical messages, making all nervous system functions possible. *“Wiring” for the nervous system’s information circuits.

sensory, interneurons, motor

List and describe the 3 classes of neurons based on their function.

unipolar, bipolar, multipolar

List and draw the 3 classes of neurons based on their structure.

2 main functions of neurons

a. conduction route for transmission of info from CNS to all other areas of body

b. communication within the CNS to integrate information

resting membrane potential across the cell membrane

membrane potential maintained when the neuron is not conducting electrical signals; usually around -70millivolts

What causes an action potential

membrane potential of an active neuron = nerve impulse transmission; caused by a stimulus on the resting neuron membrane.

Resting state

more K+ on the inside of the cell and Na+ outside of the neuron (-70mV inside).

depolarization

Na+ rushes inside the neuron changing the internal membrane charge to positive

Repolarization

period of time where resting membrane potential is restored allowing K+ to flow to outside of the neuron space.

The Na+/K+ pump swaps the Na+ and K+ so that it returns to resting neuron state.

What restores the ion (Na+, K+) distribution after an action potential?

saltatory conduction

The action potential in a myelinated neuron “leaps” from node to node.

Myelinated fibers conduct impulses faster than unmyelinated because ______ ________

is faster than point-to-point

action potential reaches axon terminal

The next neuron is directly excited through a chemical synapse, or it is excited by a chemical

synapse (using neurotransmitters).

acetylcholine

Junctions with motor effectors (muscles, glands); many parts of brain; Excitatory or inhibitory; involved in memory.

dopamine

Brain; autonomic system; Mostly inhibitory; involved in emotions/moods; regulating motor control.

serotonin

Several regions of CNS; Mostly inhibitory; involved in moods/emotions, sleep.

endorphins

Several regions of CNS; retina; intestinal tract; Mostly inhibitory; act like opiates to block pain.

GABA

Brain; Inhibitory; most common inhibitory neurotransmitter in the brain

frontal lobe

which lobe contains personality and decision making

parietal lobe

which lobe contains the sensory cortex and motor cortex

occipital lobe

which lobe contains the visual cortex?

temporal lobe

which lobe contains the auditory cortex; memory, emotion, language and hearing

cerebrum

which part of the brain controls sense perception, voluntary muscle contraction and

mental activities (thinking, reasoning, learning,

memory, intelligence, and sense of responsibility)

hypothalamus

which brain structure regulates and coordinates autonomic and involuntary activities (temp, hunger, thirst, etc.)

medulla oblongata

which brain structure is the vital control centers for homeostatic functions (breathing, circulation, digestion, vomiting, sneezing, swallowing, coughing, and hiccupping).

corpus callosum

Allows for communication between left and right brain hemispheres

cerebellum

controls posture, maintains balance, and coordination of motor

activity

meninges

The layers that cover and protect the spinal cord and brain—they also supply important blood vessels and nutrients to CNS.

3 layers of the meninges

Dura mater – outer layer of meninges made of strong white fibrous tissue; also serves as the

inner periosteum of the cranial bones

Arachnoid membrane – delicate, cobweb-like layer between the dura mater and pia mater

Pia mater – transparent layer that adheres to the outer surface of the brain and spinal cord;

contains blood vessels

Afferent/sensory

fibers carry nerve impulses to the CNS can be divided into somatic or viscera

efferent/motor

fibers carry nerve impulses away from CNS can be divided into autonomic or somatic

sympathetic

known as “fight or flight”; response and prepares the body for increased activity using noradrenaline.

parasympathetic

known as the “rest and digest” response and generally maintains the body during relatively quiet conditions using ACH.

components of a reflex arc

a. Stimulus (change internal or external)

b. Receptor - detects a stimulus, such as heat, pressure, or pain; responds to the external or internal stimulus and converts it into an electrical impulse.

c. Afferent pathway (sensory neuron) - transmits the electrical impulse from the receptor to the spinal cord or brain. It carries the signal toward the central nervous system (CNS).

d. Central Nervous System (integration center) - located in the spinal cord or brain. Here, the sensory neuron synapses with an interneuron, which processes the information and then relays it to the appropriate motor neuron. The

integration center decides how the body should respond to the stimulus.

e. Efferent pathway (motor neuron) - carries the response signal from the CNS to the effector. This neuron sends the command to initiate a movement or action, such as muscle

contraction.

f. Effector - the muscle or gland that carries out the response to the stimulus. It could be a muscle contracting (e.g., pulling your hand away from a hot object) or a gland secreting a substance

g. Response (resulting reaction to stimulus)

Receptor

What is 1?

sensory neuron/afferent pathway

What is 2

interneuron

what is 3

motor neuron/efferent pathway

what is 4

effector (skeletal muscle)

what is 5

generalized reflex arc

what does the diagram show

cerebrum

1

thalamus

2

hypothalamus

3

diencephalon

4

Pons

5

medulla oblongata

6

spinal cord

7

gyri

8

sulci

9

corpus callosum

10

midbrain

11

cerebellum

12

stimulus, involuntary, rapid, same way each time

what are the 4 properties of all reflexes?

somatic (afferent in PNS)

carries info from skin, skeletal muscles, & joints (external)

visceral (afferent/sensory in PNS)

carries information from visceral organs (internal)

autonomic (efferent/motor in PNS)

automatically controls smooth & cardiac muscles and glands

somatic (afferent/sensory in PNS)

consciously controls skeletal muscles

synaptic transmission

what is in the picture

cerebral cortex

Thin layer of gray matter on surface of cerebrum

hypothalamus

Maintains homeostasis by regulating visceral activities

thalamus

Receives all sensory impulses except for smell, sends them to cerebral cortex

pons

Rounded bulge on underside of brainstem; regulates breathing

brainstem

Most primitive functions in brain; Includes the midbrain, pons, and medulla oblongata

gyri

Wrinkles and bumps on the surface of cerebrum

sulci

Shallow grooves on surface of cerebrum

medulla oblongata

Regulates cardiac, vasomotor and respiratory activities

cerebrum

Determines personality and intelligence

midbrain

Part of brainstem between diencephalon and pons

hippocampus

Processes memories

transverse fissure

Separates the occipital lobe & cerebellum

cerebrospinal fluid

Maintains ion balance in CNS

spinal cord

A portion of the CNS; a slender column of nervous tissue

ventricles

Produces cerebrospinal fluid

meninges

Protective membrane between bone and soft nervous tissue

limbic system

Controls emotions and feelings

temporal lobe

Stores memory of visual scenes, music, and complex patterns; understands speech

frontal lobe

Responsible for thinking, planning, and problem solving

Pituitary gland

Sits in a bony cavity attached by a thin stalk to the hypothalamus at the base of the brain; produces and stores several hormones.

spinal cord

examine this picture. what is it a diagram of?

sequence of events of a nerve impulse

1. sodium channels open and sodium ions diffuse inward

2. the membrane becomes depolarized

3. potassium channels open and potassium ions diffuse outward

4. the membrane becomes repolarized