anatomical organization of the nervous system

Question 1

what is included in the CNS?

Answer 1

Brain which includes CEREBRUM, BRAINSTEM, AND CEREBELIUM; Spinal Cord. Axiall

Question 2

what is the difference between a tract and nerves?

Answer 2

a tract is a collection of axone in CNS and a nerve is a collection of axones in PNS

Question 3

Types of nerves?

Answer 3

motor (spinal cord and muscles) sensoriel (muscles to the brain)

Question 4

what is an axone?

Answer 4

it is a cytoplasm connection that conducts electrical signal

Question 5

what is the function of CNS

Answer 5

is it to integrates, processes, to coordinate sensory (afferent) data and motor(efferent) command it is the seat of higher functions like intelligence, memory learning and emotions

Question 6

what is a neuron?

Answer 6

it is a the functional unit of the cell. it encodes information and conduct it over considerable distances and transmit it to other neurons or non-neuronals cells.

Question 7

CNS is the seat of which functions?

Answer 7

intelligence, memory, learning and emotions.

Question 8

What is te functions of PNS?

Answer 8

Carries sensory information from receptors to CNS - afferent dividion. it also carries motor commands from tthe CNS to peripheral tissues and systems- efferent division

Question 9

where do we find Purkinje neuron

Answer 9

in cerebellum, multipolar

Question 10

functions of the neurons

Answer 10

transmit information to other cells, signaling is both electrical (common in the axone) and chemical ( synthesis, transport and release of neurotransmitters at the synaptic terminal)

Question 11

what is the difference between afferent and efferent neurons?

Answer 11

Afferents are sensory neurons, carrying nerve impulses from sensory stimuli toward the central nervous system and brain. carry signals to the brain and spinal cord as sensory data and are located near the brain and spinal column compromizing the CNS. Meanwhile efferent nerves are motor neurons, carrying neural impulses away from the central nervous system and toward muscles to cause movement. Efferent neurons send signals from the brain to the muscles, glands, and organs of the body in response to sensory input. The cell bodies of efferent neurons are located within the central nervous system. Their purpose is to take signals from the central nervous system to: PNS, muscles and glands.

Question 12

what is a myelin sheath (fatty membran around an axon)

Answer 12

it is formed by specialized neuroglial cells (Oligodendrocytes in CNS and Schwan cells in PNS), it also forms insulating layer around axon and it helps to speeds the rate of impulse conduction

Question 13

myelinated vs unmyelinated

Answer 13

rapid transmission of nerve impulse vs slower transmisssion of nerve impulse

Question 14

what is satelitte cells?

Answer 14

surround sensory neuron cell body in DRG, regulates O2, CO2 and neurotransmitters

Question 15

what are Schwann cells?

Answer 15

surround all sensory neurons, myelinates peripheric axons and also provides support for unmyelinated axonsa and participates in regeneration

Question 16

what are oligodendrocytes?

Answer 16

they are myelinated in CSN axones which provides structural framework

Question 17

what are Astrocytes?

Answer 17

they maintain blood-brain barrier, regulate ion, nutrient and dis

Question 18

synapse

Answer 18

Point of contact of an axon terminal with another nerve or target cell. Transmits nerve impulse via chemical neurotransmitters. it is an unidirectional flow. Point of contact of an axon terminal with another cell, it transmits nerve impulse via neurotransmitter

Question 19

how many classes of cells have the nervous system?

Answer 19

2 distinct classes of cells which are both essentiel for neuronal signaling
Neurons which generates, transmit and integrate impulses 
Neuroglial cells (glia) which support and protect neurons as well as it forms the connective tissue of the nervous system (schwan and satellite (PSN)) and (oligo, astocyte, microglia and ependymal cells (CNS))

Question 20

What are ependymal cells?

Answer 20

line ventricles (brain) and central canal (spinal cord) which help produce, circulate and monitor cerebrospinal fluid

Question 21

Grey matter

Answer 21

cells body= nucleus. collection of neuronal cell bodies, dentrites, unmyelinated axons. it appears grey because it lacks myeline

Question 22

White matter

Answer 22

it has this color because of myelin. -aggregates of myelinated fibers

Question 23

distribution of grey and white matter

Answer 23

brain-Cerebral cortex ( G outside & W inside)

spinal cord- G inside & W outside

Question 24

what are the three membrans in the PNS

Answer 24

endoneurium, perineurium and epineurium

Question 25

what is Dorsal root ganglia

Answer 25

it contains cell bodies of primaty sensory neurons which originates from progenitor cells of ectodermal origin. pseudounipar neurons which are all sensory (axon split into two branches one peripheral and the other central) has nuclei in the centre of the cell and the nerve cell bodies is surreounded by a layer of supporting satellite cells.

Question 26

different functions of Dorsal root ganglia

Answer 26

it can identify cell bodies based on their sensation (heat, cold, pain, light, touch, proprioceptive) and are all located in the same ganglia

Question 27

autonomic nervous system

Answer 27

involuntary visceral function, has general homestasis and is divided into sympathetic and parasympathetic

Question 28

what is an autonomic ganglia

Answer 28

it contains cell bodies of postsynaptic motor neurons, is multipolar neurons, nucleus eccentrically located and the satellite cell sheath is less apparent

Question 29

Ganglion vs Nuclei

Answer 29

ganglia is a group of neurons in PNS and nuclei in CNS