exam one million study x_x

What are the functions of the nervous system?

Maintains Homeostasis

Recevies Sensory Input

Inergrating Information

Sending Motor Output

Establishing & Maintaining Mental Activity

What structures make up the central nervous system and what body cavity can you find them in??

The central nervous system is made up of the brain and spinal cord. They are found in the cranial cavity and vertebreal cavity.

What are neurons?

Electrically excitable cells of the nervous system; composed of cell bodies and axons. They transmit nerve impulses and communicate between the brain and body.

What are glial cells?

Supportive cells with any functions

What are the two major subdivison of the nervous system?

Central Nervous System and Peripheral Nervous system

What is the peripheral nervous system composed of?

Nerves and ganglia

How many cranial nerve pairs are there?

There are 12 pairs

How many spinal nerve pairs are there?

There 31 pairs

What is the sympathetic system

Part of the autonomic Nervous System, reffered to as “fight or flight” it prepares the body for action, stress or danger

What is the autonomic nervous system

Part of the peripheral nervous system and regulates involuntary physiological processes essential for survival, such as heart rate, blood pressure, respiration, digestion, and sexual arousal

What is the parasympathetic system?

Responsible for the “rest and digest” state that calms the body after stress.

What are satellite cells?

These celles surround nerve cell bodies in gaglis of PNS; provide insulation around the cell body and regulate chemical enviroment.

What are schwann cells

The cells envelop axons of PNS, form myelin sheat, and assist in regernartion of damaged fibers.

True of False- The myelin sheath is formed by Schwann cell in PNS

TRUE

What does the myelin sheath consist of?

80% Lipid and 20% Protein, and the plasma membrane of schwann and oligodendrocytes

What is the typicall mV of a neuron in “rest”

-70 millivolts

What does negative value indicate?

It indicates a more negatively charged particle on the inside of the membrane compared to the outside.

TRUE OR FALSE- Neurons in the PNS are always capable of repair while those in the CNS are not.

FALSE

What is action potential??

Rapid up-and-down change in voltage produced by the coordinated opening and closing voltage-gated ion channels

What does threshold mean?

The minimus voltage to opne voltage-gated channels

What is the minimum voltage to reach threshold?

-55 mV

Types of glia found in the central nervous system

1. Astrocytes

2. Oligodendrocytes

3. Microglia

4. Ependymal

Types of glia found inthe peripheral nervous system

1. Schwann

2. Satellite

What are astrocytes

Glis found in the centreal nercous system that nourish the neurons, guide migrating neurons, control chemical enviroment

What are microglia

Glia that clean up the neuronal debris of phagocytes

What are ependymal cells

they line hte central cavities of the brain and the spinal coumn; also form a permeable barries between CNS and the tissue fluid.

What are ogliodendrocytes?

They make up the myelin sheath in the CNS

What do Schwann cells do

Form myelin sheath in the PNS

What is a synapse

Point where an axon terminal meets the next cell.

What is the presynaptic terminal?

The specialized distal end of an axon that releases neurotransmitters to send signals to a postsynaptic neuron, muscle, or gland. It translates electrical action potentials into chemical signals via exocytosis of neurotransmitter-filled vesicles, which occurs at a specialized region called the active zone.

What is a synaptic cleft

Gap between presynaptic neruon and postsynaptic neuron

What is the postsynaptic membrance.

Specialized, receptor-dense portion of a neuron or muscle cell plasma membrane that receives neurotransmitters from the presynaptic neuron across the synaptic cleft. It initiates cellular responses—excitation or inhibition—by opening ion channels to alter the cell's membrane potential, acting as the receiving component in neural communication

What are sensory neurons

Nerve cells in the peripheral nervous system that convert external and internal stimuli—like light, sound, touch, and temperature—into electrical impulses. (TOWARDS AS)

What are Motor Neurons

Nerve cells that transmit signals from the central nervous system (brain and spinal cord) to muscles and glands, initiating voluntary and involuntary movements ( AWAY FROM CNS)

What are interneurons?

Neurons in the central nervous system (CNS) that act as intermediaries, connecting sensory and motor neurons to process information, coordinate reflexes, and regulate neural activity.

What is a multipolar neuron

Most common neuron in CNS; type of motor neuron

What is a bipolar neuron

Neurons with one main dendrite and one axon; found in the retina of the eye

What is a pseudounipolar neuron

Sensory neuron with one process extending from the cell body that splits into two branches: one extending to the periphery (sensory receptor) and the other to the central nervous system (spinal cord/brain).

Nodes of Ranvier

Gaps in the myelin sheath of an axon

Axon hillock

Area where the axon joins the cell body

Initial segment

First portion of the axon, closest to the axon hillock

Gray matter

Contains neuronal cell bodies, dendrites, axon terminals, unmyelinated axons and neuroglia