Question 1

Nerve impulses speeds vary widely depending on nerve fiber type, with the fastest signals reaching how many meters per seconds? How much does slower ones travels ?

Accepted Answer

120 meter per seconds/ abt 270 mph., myelinated axons. Slower travels 0.5 -2 meter per second in small, unmyelinated fibers

Question 2

Fast moving nerves characteristics and functions.

Accepted Answer

Characteristics: Large diameter and myelinated (covered in fatty tissue) 
Functions: carrying rapid signals for motor commands and senses touch and proprioception.

Question 3

Slow moving nerves characteristics and functions

Accepted Answer

Characteristics: Smaller diameter and unmyelinated. 
Functions: carrying slower signals such as those for pain and temperature.

Question 4

Why speeds vary? Myelination:

Accepted Answer

the presence of Myelin, an insulated sheaths, dramatically increases the speed of nerve impulses. W/out it, signals must be regenerated along the axon, a process that is much slower.

Question 5

Why speed varies? axon diameter:

Accepted Answer

Thicker axon can conduct signals faster than thinner ones.

Question 6

Why speed varies? Functions:

Accepted Answer

The body has evolved different speeds for different functions. Ex: a fast response is needed for muscle control, while a slower response is sufficient for pain.

Question 7

What is nervous system?

Accepted Answer

The master controlling and communicating system of the body

Question 8

Nervous system cells communicate by?

Accepted Answer

-Electrical signals 
-signals are:
—— rapid, specific and usually cause an almost immediate response.

Question 9

Sensory input

Accepted Answer

Uses sensory receptors (effectors organs: muscles and glands that carry out response to a signal from nervous system) to monitor changes inside and outside the body.

Question 10

Integration

Accepted Answer

Process and interpret sensory input and decide what should be done

Question 11

Motor Output

Accepted Answer

Provide a response by activating effector organs (muscles and glands)

Question 12

Organization of the nervous system 1

Accepted Answer

Central Nervous system: Brain and spinal cord: Integration and command center

Question 13

Organization of the Nervous System 2

Accepted Answer

Peripheral Nervous System- Paired spinal and cranial nerves 
-Cranial Nerves- Nerves connected to the brain or brain stem 
-Spinal Nerves- nerves attached to the spinal cord

Question 14

Organization of the Nervous System 3

Accepted Answer

Spinal nerve carry messages to and from the CNS 
-Sensory - Commands PNS to CNS 
-Motor - Commands CNS to PNS

Question 15

Peripheral Nervous System

Accepted Answer

The peripheral nervous system (PNS) is the network of nerves and ganglia outside the brain and spinal cord that connects the central nervous system (CNS) to the rest of the body. Divided into somatic nerves. Control involuntary movements and autonomic nervous system, which controls involuntary functions like heart rate and digestion.

Question 16

PNS

Accepted Answer

Responsible for sending sensory information to the CNS and carrying motor commands from the CNS to muscles and organs.

Question 17

Divisions of PNS - sensory (Afferent) Divisions

Accepted Answer

Conducts impulses from receptors to CNS

Question 18

Two functionals Subdivisions

Accepted Answer

1-Somatic sensory - nerve fibers- conduct impulses from skin, skeletal muscles and joints. 
2- visceral sensory nerve fibers- conduct impulses from visceral organs within the ventral body cavity.

Question 19

Motor (Efferent) Division

Accepted Answer

Conducts impulses from the CNS to effectors (muscles and glands) 
Two main parts 
1-Somatic Nervous System
2- Autonomic Nervous System

Question 20

Motors Divisions

Accepted Answer

-Somatic Nervous Syatem:
-somatic motor (voluntary) 
- conduct impulses from the CNS to skeletal muscles

Question 21

Motor División 2

Accepted Answer

Autonomic Nervous System (ANS) 
-Visceral motor: (involuntary) 
- Conducts impulses from the CNS to Cardiac muscles, smooth muscles, and glands.

Question 22

Two functional subdivisions of ANS

Accepted Answer

1) Sympathetic Division 
-Movilizes Body systems during activity (fight or flight) 
-Concerned with elevation of metabolic rate and increased alertness. 
2) Parasympathetic Division
-Conserves energy
-Lowers the metabolic rate

Question 23

Nervous system structures

Accepted Answer

1-Neurons - Cells generating and transmitting elect. Signals 
2-Nerve- Bundles of neurons (nerve fibers) blood vessels and connective tissues 
3-Neuroglia- (Glia cells) - cells that support, protect and insulate neurons. 
4- Ganglion- a collection of nerve cells bodies. (Brain, spinal cord, cranial nerves, spinal nerves, peripheral nerves and sensory receptors.

Question 24

Neuralgia of the CNS 1

Accepted Answer

Astrocytes- the most abundant type of glial cell in the central nervous system (cns) they perform multiple essential functions that support, protect ñ, and regulate neural activity. 
-Repair and heal
-maintain CNS environment 
-provide structural support 
-Guide neuronal development

Question 25

Neuralgia of the CNS 2

Accepted Answer

Microglia- 
-acts as phagocytes and clean up cellular debris, waste products and pathogens of the CNS. 
Oligodendrocytes- 
-wrap around axons to form myelin sheaths which insulates them.

Question 26

Ependymal celos

Accepted Answer

Form the epithelial membrane (epemdyma) lining the central canal of the spinal column and ventricles of the brain. 
-Have cilia and microvilli ghat circulates CSF 
-Monitor CSF 
-contains stem cells for repair 
-Choroid Plexus, located in the ventricles of the brain produces cerebrospinal fluid (CSF)

Question 27

Neuroglia of the Peripheral Nervous System (PNS)

Accepted Answer

Two main types of glial cells:
-Satellite cells 
-Schawnn cells 
Both provide structural metabolic and protective support to peripheral neurons

Question 28

Dendrites

Accepted Answer

Slender processes that extends out from the cell body. Contains fine branches called dendritic spines. 
-Neurons receive information from other neurons at the dendritic spines, with conduct electrical impulses to the cell body

Question 29

Axon

Accepted Answer

A long process that conducts electrical signals (actions potentials) away from the cell body. 
-Axoplasm- (cytoplasm) of the axon contains neurofibrils, neurotubules, small vesicles, lysosomes, mitochondria and various enzymes.

Question 30

Axolema

Accepted Answer

Plasma membrane surrounding the axoplasm

Question 31

Axon Hillock

Accepted Answer

Cone shaped area of te cell body that narrows into the initial segment of the axon.

Question 32

Axons 2

Accepted Answer

Some axons contains branches known as collaterals- allowing a single axon to communicate with several nerve cells (neurons) 
Axons end in a series of fine extensions called telodendria. 
The distal endings of the telodendria have a knob- like shape cells called synaptic terminals (knobs)

Question 33

Axoplasmic transport

Accepted Answer

Neurotransmitters are synthesized in the cell body and transported to the synaptic knobs

Question 34

Myelin sheaths

Accepted Answer

A whitish, protein-lipid substance made by Oligodendrocytes in the CNS and Schwann Cells in the PNS

Question 35

Neurons

Accepted Answer

Classified by Structures: according to the number of processes extending from their cell body 
Function: according to the direction in which the nerve impulse travels relative to the CNS

Question 36

Unipolar neurons

Accepted Answer

One process extends from the cell body and divides a T-like

Question 37

Multipolar neurons

Accepted Answer

Multiple processes extend from the cell body

Question 38

Transmembrane potential

Accepted Answer

When a Neuron is adequately stimulated 
-an electrical impulse is generated and conducted along the length of its axons called : ACTION POTENTIAL NERVE IMPULSE

Question 39

Extracellular fluid

Accepted Answer

Contains a high concentration of Na+ and Cl -

Question 40

Cytosol

Accepted Answer

Contains a high concentration of K+ and negatively charged proteins

Question 41

Membrane channels

Accepted Answer

Control the movement of ions accross the plasma membrane Na+ and K+

Question 42

Two main types of membranes channels

Accepted Answer

1- Leak channels (passive) 
2- Gated channels (active)

Question 43

Hyper polarization

Accepted Answer

A change in the transmembrane potential towards a more nagative value than the resting membrane potential (overshoots)

Question 44

2 types of changes in membrane potential

Accepted Answer

1- Graded Potential - local potentials - short lived localized change in the resting membrane potential. Any stimulus that opens a “chemical-gated channel” will produce graded potential 

2- Actions Potential - a brief reversal membrane potential. Once initiated, changes in the tranembrane potential propagate and affect the entire excitable membrane. 55 mV in many neurons

Question 45

The principal way neurons communicate

Accepted Answer

Follow the all-or-none principle - A stimulus either triggers and action potential or does not. 
You can’t have a partial action potential 
If the threshold is reached, an action potential will occur

Question 46

Generations of actions potential

Accepted Answer

- Depolarizations- A stimulus opens the chemical gates channels. When voyage-gated Na+ channels open, the plasma membrane becomes much more permeable to Na+. 

- Repolarizations - the process that occurs when the stimulus is removed and transmembrane potential begins to return to normal resting levels. 

-Hyperpolarization- voyage gated K+ channels begin closing as the membrane reaches the normal resting potential (-70 mV) 

Resting potential- when the action potential has ended.

Question 47

Synapse between  neuron and muscle cell: Neuron muscular Junction (NMJ)

Accepted Answer

- The synapse between a motor neuron and skeletal muscle fiber 
- uses acetylcholine (ACh) as the neurotransmitter 
-Specialized for a rapid and reliable transmission that always produces a muscle response

Question 48

Synapse

Accepted Answer

A synapse can occur between two neurons at the:
-Dendrite (axodendritic) 
-Cell body (axosomatic) 
-Axon (axoaxonic)

Question 49

2 types of Synapses

Accepted Answer

Electrical- allows direct transmission of electrical signals between cells via tal junctions. 

Chemical - transmit signals across a small gap, the synaptic cleft using chemical messengers called neutransmitters.

Question 50

Neurotransmitters

Accepted Answer

There are 50 neurotransmitters other than ACh 

Two types:
Excitatory and inhibitory 

There balance is critical for healthy movement, cognition, mood regulation and behavior

Question 51

Summation

Accepted Answer

A single nerve impulse produces an small local graded depolarization that can not induce an action potential 

Two types
1-Temporal Summation 
2- Spatial Summation

Chapter 12- (A&P 1)