Anatomy Lecture Exam 3

Front 1

The nervous system along with the endocrine system?

Back 1

Regulates functions of other body systems

Front 2

Endocrine System

Back 2

- releases hormones into the blood
- response occurs after seconds or even days

Front 3

Nervous System

Back 3

- rapid, specific electrical impulses
- response in milliseconds, almost immediate

Front 4

The brain does more than regulate organ systems:

Back 4

- integration of senses (sight, smell, hearing)
- emotions, thoughts, memory, dreams
- able to devise complex technology

Front 5

4 General Functions

Back 5

1. Sensory Input
2. Integration
3. Motor Output
4. Ability to store experiences (memory) and to learn

Front 6

Sensory Input?

Back 6

- it monitors changes inside and outside body
- using millions of sensory receptors
- the changes are called stimuli
- information gathered is called sensory input

Front 7

Integration?

Back 7

- the sensory input is interpreted
- brain decides correct response to the stimulus

Front 8

Motor Output?

Back 8

- appropriate response is elicited
- it activates effector organs: muscles or glands

Front 9

2 main divisions of the Nervous System

Back 9

1. CNS
2. PNS

Front 10

CNS?

Back 10

- brain and spinal cord
- occupies the dorsal cavity
- entirely encased in bone
- the integrating & command center
- interprets sensory input
- issues a response

Front 11

PNS?

Back 11

- everything outside the CNS
- consists of nerves and receptors

Front 12

Spinal nerves

Back 12

take impulses to and from the spinal cord

Front 13

Cranial nerves

Back 13

take impulses to and from the brain

Front 14

Receptors

Back 14

- specialized cells that respond to stimuli
- rods & cones - respond to light
- Meissner’s corpuscle - discriminative touch

Front 15

2 divisions of the PNS

Back 15

1. Sensory or Afferent division
2. Motor or Efferent division

Front 16

Sensory/Afferent Division

Back 16

- nerve fibers that:
convey impulses from receptors to the CNS
- keeps CNS informed of everything going on inside and outside body

Front 17

2 categories of sensory fibers

Back 17

1. Somatic afferents - impulses from the skin, muscles, joints
2. visceral afferents - impulses from organs of the ventral cavity

Front 18

Motor/Efferent division

Back 18

- nerve fibers that transmit impulses from CNS to effectors
- activate muscles & glands
- they cause the response

Front 19

2 categories of motor fibers

Back 19

1. Somatic nervous system
- conveys impulses to skeletal muscle
- allows voluntary control of skeletal muscles
2. Autonomic nervous system
- conveys impulses to all other effectors:
smooth and cardiac muscles and glands
- regulates events that are automatic

Front 20

2 subdivisions of autonomic nervous system

Back 20

1. The sympathetic nervous system
- prepares the body for “fight or flight”
2. the parasympathetic nervous system
- prepares the body for “rest and digestion”

Front 21

2 major cell types of the Nervous System

Back 21

1. Neuroglial cells
2. Glial cells

Front 22

Neuroglial cells

Back 22

- supportive, insulate & protect
- do not transmit electrical impulses
- mitotic, smaller, more numerous
- 4 types in the CNS

Front 23

4 types of Neuroglial cells

Back 23

1. Astrocytes
2. Microglia
3. Ependymal
4. Oligodendrocytes

Front 24

Astrocytes

Back 24

- most abundant
- large, star shaped cells
- anchor neurons to blood vessels
- nutrient exchange
- control content of ECF

Front 25

Microglia

Back 25

- smallest, resemble astrocytes
- “WBCs” of CNS - phagocytic
- increase in numbers in infection
- migrate to infection site
- phagocytize bacteria, cellular debris

Front 26

Ependymal

Back 26

- line ventricles, secrete CSF
- shapes vary (squamous - columnar)
- many ciliated

Front 27

Oligodendrocytes

Back 27

- cytoplasm contains a lipid called myelin
- wrap around neurons: provide myelin sheath

Front 28

2 types of glial cells in the PNS

Back 28

1. Satellite cells
2. Schwann cells

Front 29

Satellite cells

Back 29

may help control EC chemical enviornment

Front 30

Schwann cells

Back 30

- cytosol contains myelin
- provide myelin sheath in the PNS

Front 31

Neurons (Nerve Cells)

Back 31

excitable:
receive and transmit action potentials (AP)
secretory (neurotransmitters)
amitotic
absolutely dependent on oxygen
don’t store glycogen
can’t use anaerobic glycolysis
vary in size and shape but have 2 common features:

Front 32

2 common features of Neurons

Back 32

1. Cell Body (Soma)
2. Processes

Front 33

Cell Body (Soma)

Back 33

enlarged portion containing the nucleus
Nissl bodies
Specialized RER (protein maker)

Front 34

Processes

Back 34

fibers extending from the cell body
2 types: Dendrites and Axon

Front 35

Dendrites

Back 35

the “receiving end” of the neuron
receive signals from other neurons
transmit them to the cell body
0 – 100s
never myelinated

Front 36

Axon

Back 36

Axon = nerve “fiber”
generate and transmit action potentials
usually away from the cell body
usually only on axon
extends to the next cell
may be short or very long (4-5 ft)
soma in cord, axon extends to effector (muscle or gland)

Front 37

Axon: distal end branches into?

Back 37

Axonal terminals

Front 38

axon terminal branches end in a swelling:

Back 38

Synaptic knob

Front 39

synaptic knob separated from adjacent cell by a tiny gap:

Back 39

Synaptic cleft

Front 40

when AP reaches synaptic knobs

Back 40

a neurotransmitter is secreted into cleft
which will excite or inhibit adjacent cell

Front 41

Synapse

Back 41

the junction between neurons or between neuron and effector cell

Front 42

Myelin Sheath

Back 42

Many axons are wrapped with a white, fatty, segmented sheath

Front 43

Nodes of Ranvier

Back 43

Segmented gaps in the sheath

Front 44

Functions of Myelin Sheath

Back 44

Insulates the neuron
Speeds transmission of the action potential
Axolemma exposed only at nodes
Necessary for normal function

Front 45

Multiple Sclerosis

Back 45

Myelin sheath becomes sclerotic
Neuron transmission is interrupted
Muscles innervated by the affected neurons are paralyzed
Blindness
Autoimmune disease
Immune cells attack myelin
Immunosuppressants

Front 46

Somas are clustered why?

Back 46

for safety

Front 47

Nucleus

Back 47

cluster of cell bodies in the CNS

Front 48

Ganglion

Back 48

cluster of cell bodies in the PNS

Front 49

Tract

Back 49

cluster of fibers in the CNS

Front 50

Nerve

Back 50

cluster of fibers in the PNS

Front 51

CNS is composed of what types of matter?

Back 51

Gray matter and white matter

Front 52

Grey Matter

Back 52

unmyelinated
Somas, dendrites, unmyelinated axons

Front 53

White Matter

Back 53

myelinated fibers ( a tract)

Front 54

Neuron structure

Back 54

Number of processes
3 types: multipolar, bipolar, unipolar

Front 55

Mulitpolar

Back 55

3 or more processes
most common

Front 56

Bipolar

Back 56

2 processes
one axon, one dendrite
extending in opposite directions

Front 57

Unipolar

Back 57

one process
immediately bifurcates
most sensory neurons

Front 58

Neuron Functions

Back 58

Direction impulse travels relative to the CNS
3 types: Sensory, Motor, Interneuron

Front 59

Neuron Function: Sensory

Back 59

impulses conducted TOWARD CNS
sensory information from receptors
unipolar

Front 60

Neuron Function: Motor

Back 60

impulses conducted AWAY FROM CNS
signals out to the effectors
multipolar

Front 61

Neuron Function: Interneurons

Back 61

in between sensory and motor neurons
make up the CNS
99% of neurons

Front 62

Nerve?

Back 62

Bundle of nerve fibers (axons) with CT wrappings
PNS

Front 63

Endoneurium

Back 63

Fine, loose CT
Several fibers gather into a bundle: Fascicle

Front 64

Perineurium

Back 64

Wraps the fascicles
Slightly heavier CT

Front 65

Epineurium

Back 65

Bounds Fascicles together
Tougher fibrous sheath

Front 66

Bulk of the nerve...

Back 66

is myelin and CT
also carries a blood supply and lymph supply

Front 67

Most nerves are mixed:

Back 67

Carrying both sensory and motor fibers
Pure sensory or motor nerves are rare
(olfactory, auditory?)

Front 68

Neuromuscular Junction (NMJ)

Back 68

Synapse between the somatic motor neuron and a skeletal muscle fiber

Front 69

Neurotransmitter contained in:

Back 69

Synaptic vesicles in synaptic knob

Front 70

NT at the NMJ is:

Back 70

Acetylcholine (ACh)

Front 71

The region of sarcolemma involved in the synapse is the:

Back 71

motor end plate
Contains receptors for ACh
Receptor proteins that bind ACh

Front 72

Excitation of the muscle cell: (6 steps)

Back 72

1 AP arrives at synaptic knob
Exocytosis of synaptic vesicles
Ach secreted into cleft
Diffuses across

2 ACh binds to receptor on motor end plate

3 Triggers a muscle cell action potential

4 Transmission of muscle AP along sarcolemma
opens Ca++ channels in SR membrane

5 Cross bridge formation, contraction

6 Back at the synaptic cleft:
ACh is rapidly broken down by:
Acetylcholinesterase (AChE)
NZ present in the synaptic cleft

Front 73

Several drugs and toxins block events at the NMJ:

Back 73

Botulinum toxin, Curare, Myasthenia gravis, Anticholinesterase Agents

Front 74

Botulinum toxin

Back 74

Produced by bacteria that proliferate in improperly canned foods
Very lethal
Blocks Exocytosis of synaptic vesicles at NMJ
No ACh – no muscle contraction
Paralysis

Front 75

Curare

Back 75

A poisonous plant derivative
Blocks the ACh receptor
but doesn’t stimulate muscle fiber
no depolarization – no contraction
paralysis
used in surgery

Front 76

Myasthenia gravis

Back 76

Progressive autoimmune disease
Antibodies block ACh receptors
Shortage of ACh receptors at motor end plate
Disease progresses – fewer receptors
Skeletal muscle weakness → paralysis

Front 77

Anticholinesterase Agents

Back 77

Inhibit acetylcholinesterase
Slows removal of ACh
ACh available longer to bind with receptors
Used for:
Treatment of myasthenia gravis
Reversal of curare poisoning

Front 78

Reflex Arc

Back 78

The neural pathway over which a reflex occurs

Front 79

Reflex

Back 79

Rapid, predictable, involuntary response to a stimulus
Often unlearned, unpremeditated
Can occur before consciousness of stimulus
Interneurons quickly inform the brain

Front 80

Simple Reflex Arc

Back 80

Simplest reflex has no interneurons
5 components: Receptor, Sensory neuron, Integration Center, Motor neuron, Effector organ

Front 81

Simple Reflex Arc: Receptor

Back 81

receives the stimulus

Front 82

Simple Reflex Arc: Sensory (afferent) Neuron

Back 82

Conducts impulse to the spinal cord (CNS)

Front 83

Simple Reflex Arc: Integration Center

Back 83

simple reflexes
afferent synapses directly with efferent

more complex reflexes:
afferent fiber synapses with interneurons
sending signals to other levels of the CNS

Front 84

Simple Reflex Arc: Motor (efferent) neuron

Back 84

conducts APs from the CNS to effector

Front 85

Simple Reflex Arc: Effector Organ

Back 85

muscle fiber or gland
somatic reflex: activates skeletal muscle
autonomic (visceral) reflex:
activates smooth, cardiac muscles, glands

Front 86

Patellar reflex

Back 86

CNS monitors body position using:
Stretch receptors in muscle and tendons
Quadriceps inserts onto tibial tuberosity
Via patellar ligament

Front 87

Patellar reflex: Tapping the tendon

Back 87

1 Stimulates stretch receptors in quadriceps.

2 APs conducted to spinal cord via sensory neuron.

3 Sensory neuron synapses with interneurons and motor neurons in the Integration center

4 APs conducted via the motor neuron,

5 to activate the effector:
the quadriceps contracts
extending knee, relieveing stretch
interneurons inhibit antagonist muscles (?)
forcing them to relax
so they won’t resist the contraction

Front 88

Regulate functions of other body systems by chemical means

Back 88

The Nervous and Endocrine Systems

Front 89

Endocrine

Back 89

Releases hormones into ECF
Hormones travel everywhere the blood goes
Responses is slower and prolonged

Front 90

Exocrine Glands

Back 90

Secrete products through a duct onto a surface
Mucous, sweat, oil, salivary, liver, mammary

Front 91

Endocrine Glands

Back 91

“ductless”, secrete hormones in ECF
have a rich blood supply
hormones diffuse into blood

Front 92

Hormone

Back 92

a chemical messenger that travels in the blood and affects the metabolism of other cells

Front 93

2 major chemical types of hormones

Back 93

1 Amino acid based (polar or hydrophilic)
2 Steriod hormones (nonpolar, hydrophobic)

Front 94

Amino Acid Based Hormones

Back 94

may be simple amino acid derivatives OR
peptides (short chains of amino acids) OR
proteins

Front 95

Steroid Hormones

Back 95

lipid, made from cholesterol
hormones produced by the:
gonads
adrenal cortex
all others are amino acid derivatives

Front 96

Hormones only exert effects on.... Cells that have a receptor for that hormone

Back 96

Target Cells or Target Organs
The receptor is located:
On the plasma membrane for a hormone
Inside the cell for steroid hormones

Front 97

Major Endocrine Glands

Back 97

1. Hypothalamus
2. Pituitary Gland
3. Thyroid Gland
4. Parathyroid Gland
5. Adrenal (suprarenal) Glands
6. Pancreas
7. Gonads
8. Pineal Gland
9. Thymus Gland