Nervous system

What is a neroun?

Nerve cell

What does a cell body contain?

most cellular organelles

What does a dendrite do?

Conducts impulses towards the cell body

What is the structure of a dendrite?

Short, branched fibers

What does a axon do?

conducts impulses away from the cell body

What are the two types of neurons?

Sensory (afferent)

motor(efferent)

What does the sensory neurons do?

the sensory messages are sent to the central nervous system

the sensory neurons detects the environment around them

What does the motor neurons do?

The motor neurons messages are sent away from the central nervous system

The motor neurons allow both involuntary and voluntary movements

What is neurogilia?

Its the glue between neurons

supports/protects cells between neurons, health/growth

Several different types in the body

What neuroglia forms a myelin sheath?

Schwann cells

What is the function of myelin sheath?

Increases the speed of nerve impulses

What are the neurons called without a myelin sheath?

Unmyelinated

What can happen if we have a loss or destruction of myelin sheath?

several disorders

What is it called when a myelin sheath is loss or destroyed?

demyelination

What are a cluster of cell bodies called outside the central nervous system?

ganglion

what are a group of axons called outside the central nervous system?

nerves

What are a group of cell bodies called inside the central nervous system?

grey matter

What are a collection of axons called inside the cns

tract

what are a group of tracts called inside the cns

white matter

Why are a group of tracts called white matter?

because of the myelin sheath covering the axons

what is the distribution of white and grey matter in the brain?

outside-white

inside-grey

what type of sensations are the sensory/afferent system in charge of?

sight, hearing, smell, sense of movement

What are the motor/efferent system in charge of?

responding to the senses

What is the somatic nervous system?

efferent neurons under voluntary control, making the brain send messages to the skeletal muscle

What is the autonomic nervous system?

efferent neurons under involuntary control

“automatic” moves on its own the brain sends messages to the smooth muscle, heart, glands

What is the organization of the nervous system?

Pns-sensory/afferent-motor/efferent-somatic-autonomic-sympathetic-parasympathetic

What are the functions of the sympathetic system?

emergency system known as the fight or flight system

increases heart rate

bronchodilation

decrease in peristalsis

increase in sweat gland secretion

inhibit voiding

What are the functions of parasympathetic system?

Control under normal conditions, known as rest and digest

decrease in heart rate

Bronchoconstriction

increase in peristalsis

increase in digestive juice secretion including saliva

micturition reflex

defection reflex

What are meninges?

set of connective tissue membranes that surround the cns

What does the meninges consist of?

brain and spinal cord

What are the 3 membranes in the meninges, inside to outside?

pia mater

arachnoid mater

dura mater

What are the functions of meninges?

cover and protect the cns

protects blood vessels and creates a protective framework around venous sinuses

What is venous sinuses?

blood channels in your brain, that carry used blood that is low on O2 away from the brain and toward the heart

What fluid is in the meninges and where is it located?

cerebrospinal fluid, found between the arachnoid mater and pia mater

How many brain ventricles are there?

4

What are the names of the 4 brain ventricles?

Lateral ventricle

third ventricle

cerebral aqueduct

fourth ventricle

What are the brain ventricles filled with?

cerebrospinal fluid

What are the functions of the cerebrospinal fluid?

forms a cushion that allows floating to the cns organs

prevents brain from crushing under its own weight

protects cns from blows and other trauma

nourishes the brain and carries chemical signals throughout it

What does the cerebrum control?

reading, writing, speaking, thinking, remembering, feeling and moving

What type of function does the cerebrum have?

motor function

What are the four external lobes that the cerebrum has?

frontal

parietal

temporal

occipital

What does the thalamus do?

receives and passes on sensory info such as pain, temp, light touch, pressure these are afferent transmissions

What is the thalamus associated with?

pain and pleasure

What happens when you combine the thalamus and hypothalamus together?

a structure called diencephalon

Where is the hypothalamus found?

under the thalamus

what does the hypothalamus control?

the autonomic nervous system, this controls heart rate, body temp, movement of food, appetite, thirst, sleep which all=homeostasis

What can the hypothalamus make and how?

makes hormones by acting on the pituitary gland

What link is the hypothalamus linked to?

between nervous and endocrine systems

Where is the brain stem located?

section between the brain and spinal cord

What does the brain stem pathway provide?

its for axons between higher and lower brain centers

What does the brain stem control?

automatic behaviors

What are the 3 parts of the brain stem?

mid brain

pons

medulla oblongata

what does the midbrain do?

its the reflex center for head and eye movement in response to sight and sounds

Where is the pons located?

its the inflated brain stem region between midbrain and the medulla oblongata

Where is the pons bridge located between?

cerebellum and brain stem

What passes through the pons?

sensory and motor fibers

What does the pons help regulate?

breathing

Where is the medulla oblongata located?

the lowest part of the brain system

What occurs in the medulla oblongata?

crossover of motor fibers

What does the cardiovascular center do?

regulates heart rates

What does the respiratory center do?

regulates rate and depth of breathing

what does the vasomotor center do?

regulates blood pressure

What else does the medulla oblongata regulate?

swallowing, sneezing and vomiting

What does the cerebellum do?

helps provide precise timing and appropriate patterns of skeletal muscle contractions in order for good coordination

helps maintain posture

maintain equilibrium using sensory input from the inner ear

how many pairs of cranial nerves are there?

12 pairs

How many pairs come from the brain stem?

10 pairs

how many pairs come from the cerebrum?

1 pair

how many pairs come from the thalamus?

1 pair

What are the 3 pairs of the sensory nerves?

olfactory

optic

vestibulocochlear

What are the 5 pairs of motor nerves

oculomotor

trochlear

abducens

accessory

hypoglossal

What are the 4 pairs of mixed?

trigeminal

facial

glossopharyngeal

vagus

Where does the spinal cord start and end?

starts from the medulla and ends between the first and second lumbar vertebra

How many pairs of spinal nerves are there?

31 pairs

What types of info does the spinal cord carry?

sensory impulses from pns to brain

motor impulses from brain to pns

what direction does the nerve impulses go?

passes a nerve impulse from sensory to motor

What is a reflex arc?

fast automatic unplanned sequence of actions in response to a stimulus

What type of reflex is it if the effector is a skeletal muscle?

somatic reflex

what type of reflex is it if the effector is a smooth muscle, cardiac muscle or gland?

autonomic (visceral) reflex

What’s the first step in the reflex arc?

receptors detect a change in the environment and initiate a nerve impulse

what’s the second step in the reflex arc?

sensory neuron passes the impulse to the spinal cord

What’s the third step in the reflex arc?

spinal cord integrates the message with the interneuron and passes it directly to the motor neuron

Whats the fourth step in the reflex arc?

motor neuron transmits the nerve impulse to the effector

What is the fifth step in the reflex arc?

effector responds to the nerve impulse which is the reflex

What are the 3 key factors of the resting membrane?

sodium potassium pump-3 Na pumped out for every K pumped in

intracellular protein anions are trapped

plasma membrane is more permeable to K than Na

What is the charge inside of the resting membrane?

negative

What is more permeable in the plasma membrane?

K is more permeable than Na

What does the K leak channels allow?

allows K to leave the cell by facilitated diffusion, down its concentration gradient

Which leaks more Na or K

K leaks more than Na

What are excitable cells?

they contain a special ion channels that open upon the correct stimulus

How do leakage channels open?

they have random opening and closings

how do ligand-gated channels open?

open with a binding of a specific neurotransmitter

How do mechanically-gated channels open?

open/close in response to mechanical stimulation such as vibration, touch, pressure

How do voltage gated channels open?

open and close in response to membrane potential

What happens when the gated channels open?

ions move quickly across the membrane

the movement is down their electrochemical gradient

the voltage changes across the membrane

what is action potential

an electrical impulse that travels along the membrane of a nerve of muscle cell

what happens to the charge of the membrane during action potential

there is a reversal of charge that occurs, the inside of the membrane becomes positively charged , where the outside becomes negatively charged

What happens at a resting state for a membrane?

all gated channels are closed

what occurs in depolarization?

the voltage gated Na channels open, which allow Na to rush in the cell, which increases the membrane potential

What occurs in repolarization?

voltage gated Na channels close and voltage gated K channels open which allow K to rush out of the cell

What occurs in hyperpolarization?

voltage gated Na channels are reset but the voltage gated K channels remain open for slightly longer, this causes the membrane potential to decrease but, the Na/K pumps brings the membranes potential to resting state