ANAPHY - Nervous System

Receiving sensory input, integrating information, controlling muscles and glands, maintaining homeostasis, establishing and maintaining mental activity

Functions of the nervous system

Central nervous system and peripheral nervous system

two main divisions of the nervous system

Brain and spinal cord

Central nervous system consists of the __

Sensory division (afferent) and motor division (efferent)

peripheral nervous system consists of the __

Sensory division (afferent)

Conducts action potentials from sensory receptors toward the CNS using sensory neurons.

Motor division (efferent)

conducts action potentials from the CNS to effector organs, such as muscles and glands

Motor neurons

The neurons that transmit action potentials from the CNS toward the periphery are called __

Striated voluntary

skeletal muscles include what kind of tissues

Somatic and Autonomic Nervous System

motor division is divided into two based on the type of effector being innervated

Somatic nervous system

Motor division where the skeletal muscles are innervated

Autonomic nervous system

motor division where the the cardiac muscle, smooth muscle, and glands are innervated

Cholinergic; acetylcholine

the parasympathetic nervous system is mainly dominated by _ neurons, wherein the neurotransmitters are _

Nicotinic and Muscarinic

receptors found in parasympathetic nervous system

Parasympathetic nervous system

cholinergic

Sympathetic nervous system

adrenergic

Alpha-1 and alpha-2, beta-1, beta-2, beta-3

norepinephrine receptors include

Alpha-1 and alpha-2

Responsible for vasomotor responses or the blood vessel. An increase and decrease in blood pressure is because of your __

beta-1

The receptors that increase the heart rate when the sympathetic nervous system is activated.

Beta-2

receptors located in the lungs responsible for bronchoconstriction

Beta-3

this receptor is brown fat, responsible for thermoregulation, commonly seen in infants

Enteric system

this system is responsible for gastrointestinal functions like movement of food

Enteric Nervous System

a unique part of the peripheral nervous system. Has both sensory and motor, responsible for the response of gastrointestinal tract

Neuron

receive stimuli, conduct action potentials, and transmit signals to other neurons or effector organs.

Neuron

unit of function in the nervous system also called nerve cells

Cell body/soma, axon, dendrites

3 parts of a neuron

Axon hillock

The area where the axon leaves the neuron cell body is called the

Collateral axons

An axon may remain unbranched or may branch to form __

Multipolar, bipolar, pseudo-unipolar

types of neurons

Multipolar

most motor neurons are what type __

Multipolar neuron

type of neurons with many dendrites and a single axon

Bipolar

usually sensory neurons of eye and nasal cavity are what type of neuron

Bipolar neurons

type of neuron with one dendrite and one axon

Pseudo-unipolar neurons

type of neuron with a single axon and no dendrites; mainly transmits information

Pseudo-unipolar

sensory neurons are usually what type of neuron

Astrocytes, Ependymal cells, Microglia, Oligodendrocytes

type of glial cells in the CNS

Schwann cells and Satellite cells

glial cells in the PNS

Glial cells or neuroglia

supportive cells of the CNS and PNS, meaning these cells do not conduct action potentials.

Astrocytes

highly branched, provide structural support; regulate neuronal

Astrocytes

glial cell that serve as the major supporting cells in the CNS. In this role, astrocytes can stimulate or inhibit the signaling activity of nearby neurons.

Blood-brain barrier

the blood vessel endothelium to form a permeability barrier, called the __

Astrocytes

participate in the formation of the blood-brain barrier

Ependymal

glial cell that is epithelial-like.Line ventricles of brain and central canal of the spinal cord

Ependymal

glial cells that line the fluid-filled cavities (ventricles and canals) within the CNS. Cerebrospinal fluid

Microglia

small mobile cells, Protect CNS from infection; become phagocytic in response to inflammation

Oligodendrocytes

provide an insulating material like myelin that surrounds axons in the CNS

Schwann cells

single glial cells that provide insulating material around axons in the PNS.

Schwann cells

glial cells that form myelin sheaths around axons in the pns

Satellite cells

glial cells that are found around the cell bodies of certain neurons of the PNS. provide support and nutrition to the neurons from heavy-metal poisons

Myelin sheath

are specialized layers that wrap around the axons of some neurons

Myelinated axons

Axons with these myelin sheaths are called

Nodes of ranvier

are gaps in the myelin sheath that occur about every millimeter between the myelinated areas.

Multiple sclerosis

disease of the myelin sheath that causes loss of muscle function.

Unmyelinated axis

lack the myelin sheaths

Unmyelinated axis

these axons rest in indentations of the oligodendrocytes in the CNS and the Schwann cells in the PNS

Gray matter

matter consists of groups of neuron cell bodies and their dendrites, where there is very little myelin

White matter

consists of bundles of parallel axons with their myelin sheaths, which are whitish in color.

Nerve tracts

a collection of axons in the cns

Nerves

collection of axons in the pns

Nuclei

collection of cell bodies in the cns

Ganglion

collection of cell bodies outside the cns

Cortex

In the CNS, gray matter on the surface of the brain is called the

Nuclei

clusters of gray matter located deeper within the brain are called

Ganglion

In the PNS, a cluster of neuron cell bodies is called a

Gray matter

it is in the center of the spinal cord and it looks like a letter H or a butterfly.

White matter

outside the spinal cord and contains myelinated fibers.

Nerves

white matter of the PNS consists of bundles of axons and associated connective tissue that form nerves

Uneven distribution of K+ and Na+, and negatively charged proteins across the cell membranes

the resting membrane potential

Leak and gated channels

two types of ion channels

Leak channels

these type of channels are always open so ions can diffuse across the membrane down their concentration gradient

Gated channels

are closed until opened by specific signals

Chemically gated and voltage-gated channels

two kinds of gated channels

Excitable

Nerve cells are __ cells

Gated membrane channels

opening and closing of gated ion channels changes the permeability of the membrane to ions and can therefore change the membrane potential

Action Potentials

“Electricity” that causes depolarization and repolarization

Action potential

Depolarization and repolarization constitute an ___

Local potentials

On stimulation, chemically gated channels are opened and initiate __

Action potential

If sufficiently strong, the local potentials activate voltage-gated channels to initiate an __

Hyperpolarization

at the end of repolarization the charge of the cell membrane becomes more negative than the resting membrane potential

Action potentials

electrical signals that are conducted along the cell membrane from one region of the cell to another

Leak channels

resting membrane potentials is set by the activity of the __

Continuous conduction

in unmyelinated axons, action potentials are conducted through __

Saltatory conduction

in myelinated axons, action potentials are conducted through __

Continuous conduction

occurs when an action potential in one part of a cell membrane stimulated local currents in adjacent parts of the cell membrane, the action potential is conducted along the entire axon cell membrane

Saltatory conduction

occurs when an action potential at one node of ranvier causes a local current to flow through the surrounding extracellular fluid and through the cytoplasm of the axon to the next node. Jump from one node of ranvier to another

Synapse

is a junction where the axon of one neuron interacts with another neuron or with cells of an effector organ

Presynaptic terminal

the end of an axon forms the __

Postsynaptic membrane

the cell membrane of the dendrite or effector cell is the __

Synaptic vesicles

neurotransmitters are stored in __

Neurotransmitters

a chemical messenger that neurons use to transmit signals across a synapse to other neurons, muscles, or gland cells

Converging and diverging pathway

2 simple neuronal pathways

Converging pathway

two or more neurons synapse with the same postsynaptic neuron

Diverging pathway

the axon from one neuron divides and synapses with more than one other postsynaptic neuron

Spatial and temporal summation

two types of summation

Spatial summation

occurs when the local potentials originate from different locations on the postsynaptic neuron. Example converging pathways

Temporal summation

occurs when local potentials overlap in time

12 cranial nerves and 31 spinal nerves

two groups of the nerves of the PNS

Base of the foramen magnum to the 2nd lumbar vertebra

the spinal cord extends from __

Cauda equina

inferior end of the spinal cord is called the __

Ascending tracts

tract from the column of the spinal cord that consists of axons that conduct action potentials toward the brain

Descending tracts

tract from the column of the spinal cord that consists of axons that conduct action potentials away from the brain