Unit 4 Nervous System - PHYSIO CAP

Sulcus

A groove or depression on the surface of the brain.

Gyrus

A ridge or fold between two sulci on the brain's surface.

Fissure

A deep groove separating large regions of the brain.

Cerebrum/Cerebral cortex

The largest part of the brain responsible for higher brain functions like thought, memory, and voluntary movement.

Brainstem

The part of the brain connecting the cerebrum with the spinal cord; controls vital functions.

Reticular formation

A network of neurons in the brainstem involved in arousal, attention, and sleep-wake cycles.

Meninges

The three protective membranes surrounding the brain and spinal cord.

Dura mater

The tough, outermost layer of the meninges.

Arachnoid mater

The middle, web-like layer of the meninges.

Pia mater

The delicate, innermost layer of the meninges directly covering the brain and spinal cord.

Falx

A fold of dura mater that separates the two cerebral hemispheres.

Subarachnoid space

The space between the arachnoid mater and pia mater containing cerebrospinal fluid.

Dural sinus

Venous channels between layers of dura mater that drain blood from the brain.

Hemorrhage

Bleeding, especially within or around the brain.

Meningitis

Inflammation of the meninges, often due to infection.

Lumbar puncture

A procedure to collect cerebrospinal fluid from the lower spine for diagnostic testing.

Cerebrospinal fluid

Fluid that cushions the brain and spinal cord and circulates nutrients and waste.

Blood brain barrier

A selective barrier that prevents certain substances in the blood from entering the brain.

CNS

Central nervous system; consists of the brain and spinal cord.

PNS

Peripheral nervous system; all nerves outside the CNS.

Sensory division

Part of the PNS that carries signals from sensory receptors to the CNS.

Motor division

Part of the PNS that carries signals from the CNS to muscles or glands.

Somatic division

Part of the motor division controlling voluntary movements of skeletal muscles.

Autonomic division

Part of the motor division controlling involuntary functions of smooth muscles, cardiac muscles, and glands.

Sympathetic division

Part of the autonomic nervous system that prepares the body for "fight or flight."

Parasympathetic division

Part of the autonomic nervous system that promotes "rest and digest."

Antagonistic effect

When the sympathetic and parasympathetic systems have opposite effects on the same organ.

Neuroglia

Support cells in the nervous system that do not conduct impulses.

Myelin sheath

A fatty layer that insulates axons and speeds up nerve impulses.

Gray matter

Areas of the CNS composed mainly of neuron cell bodies.

White matter

Areas of the CNS composed mainly of myelinated axons.

Axon

The long projection of a neuron that carries impulses away from the cell body.

Permeability

The property of a membrane that determines what substances can pass through.

Depolarization

A change in a cell's membrane potential, making it more positive.

Action potential

A rapid electrical signal traveling along a neuron.

Propagation

The movement of an action potential along the axon.

Sodium potassium pump

A membrane protein that moves sodium out of cells and potassium in to maintain resting potential.

Neurotransmitter

A chemical messenger released by neurons to transmit signals across a synapse.

Reflex arc

The neural pathway that controls a reflex, typically involving sensory and motor neurons.

Endoneurium

Connective tissue surrounding individual nerve fibers.

Perineurium

Connective tissue surrounding bundles (fascicles) of nerve fibers.

Epineurium

Connective tissue surrounding the entire nerve.

Fascicle

A bundle of nerve fibers within a nerve.

Sensory nerve

A nerve that carries impulses from sensory receptors to the CNS.

Motor nerve

A nerve that carries impulses from the CNS to muscles or glands.

Mixed nerve

A nerve carrying both sensory and motor fibers.

Spinal nerves

Nerves that emerge from the spinal cord.

Dorsal ramus

Branch of a spinal nerve that innervates the back muscles and skin.

Ventral ramus

Branch of a spinal nerve that innervates the front and sides of the body.

Intercostal nerves

Nerves between the ribs that control muscles and sensation of the thoracic wall.

Nerve plexus

A network of intersecting spinal nerves.

Preganglionic neuron

A neuron that originates in the CNS and carries signals to a ganglion.

Postganglionic neuron

A neuron that carries signals from a ganglion to a target organ.

Sympathetic

Part of the autonomic nervous system that stimulates "fight or flight" responses.

Parasympathetic

Part of the autonomic nervous system that stimulates "rest and digest" responses.

Autonomic NS

The part of the nervous system controlling involuntary body functions.