1
Q
Central Nervous System
A
- made up of the brain and spinal cord
- integration and command center of nervous system
- receives sensory signals, interprets them and dictates motor response to them
2
Q
Afferent Signals
A
AKA sensory signals
- signals picked up and carried by PNS to CNS
3
Q
Peripheral Nervous System
A
- all nervous tissue outside the CNS
- made up of nerves and ganglia (clusters of neuron cell bodies)
- serve as communication lines linking body to CNS
4
Q
Efferent Signals
A
AKA Motor signals
- carried away from the CNS to effector organs, such as muscles and glands
5
Q
sensory input
A
information gathered by the nervous system
6
Q
integration
A
processing and interpretation of sensory input by the CNS
7
Q
motor output
A
the actions performed by effector organs upon receiving an efferent signal
8
Q
Subdivisions of the PNS
A
Sensory (Afferent) Division
- Somatic Sensory Receptors - outer, ie skin
- Visceral Sensory Receptors - visceral organs
Motor (Efferent) Division
- Somatic Nervous System - innervation of skeletal muscle, etc.
- Autonomic Nervous System - smooth/cardiac muscle and glands
9
Q
Somatic Sensory Perception Divisions
A
General Senses (widespread receptors)
- temperature, pain, pressure, touch (via skin)
- proprioception (joint position, postural tension, balance)
Special Senses (localized receptors)
- Smell
- Taste
- Vision
- Equilibrium & hearing
10
Q
Sympathetic Division of Autonomic Nervous System
A
- readies the body for activity
- “fight or flight”
11
Q
Parasympathetic Division of Autonomic Nervous System
A
- conserves energy and promotes digestion
- “rest and digest”
12
Q
Neurons
A
- basic structural unit of nervous system that conducts electrical impulses along its plasma membrane
- each neuron can live and function for the entire lifetime of the organism
- does not undergo mitosis
- high metabolic rate
13
Q
Neuron Properties
A
- Excitability - responds to changes in body and environment
- Conductivity - produce eletrical signals
- Secretion - releases neurotransmitters at synapses when eletrical signal reaches them
14
Q
purple structure at left containing nucleus
A
Neuron Cell Body (AKA Soma/Perikaryon)
- contains nucleus/cytoplasm
- has the usual organelles as well as specialized neuronal organelles (Nissel granules, Neurofibrils)
15
Q
Branched purple structures coming off cell body at left
A
Dendrites
- shorter than axon, but much branching
- receive signals and transmit them to cell body
16
Q
long thing cytoplasmic extension extending rightward from cell body through the yellow structures
A
Axon
- one per neuron
- Sends signals away from cell body
17
Q
Nissl Granules
A
AKA Nissl bodies
- rER and free ribosomes within neuron cell bodies
- stain densely on microscopic slides
18
Q
Neurofibrils
A
- bundles of microfilaments within neurons
- similar to structure of myofibrils within muscle cells
19
Q
Ganglia
A
clusters of neuron cell bodies outside the CNS, along PNS nerves
20
Q
cone-shaped region of cell body where it meets the axon
A
Axon Hillock
21
Q
branched ends of axon on the right
A
Telodendria
- AKA axon terminals or terminal branches
- end in synaptic knobs/bulbs at dendrites of another neuron, motor end plate, etc.
22
Q
spaces between the yellow structures on the axon
A
Nodes of Ranvier
- neurofibril nodes
23
Q
yellow cells surrounding the axon
A
Schwann cells
AKA neurolemmocytes
- form myelin sheath around axons in PNS only
24
Q
the cells that appear as small dots here amongst the neurons
A
Neuroglial Cells (or Neuroglia)
- outnumber neurons ~10 to 1
- insulate and support neurons
- branching processes and central cell body
25
Types of Neuroglial Cells
**CNS**
* **Astrocytes** - star-shaped, blood vessel connections
* **Microglia** - smallest, least abundant, phagocytes
* **Ependymal Cells** - CS fluid producers, ciliated
* **Oligodendrocytes** - myelination in CNS
**PNS**
* **Satellite Cells** - surround neurons in ganglia
* **Schwann Cells** - myelination in PNS
26
Yellow cell here connecting capillary to neuron
**Astrocyte**
- most abundant neuroglia in CNS
- star-shaped
- connect blood vessels to neurons
- contribute to BBB
- regulate ion balance and brain tissue fluid
- take up neurotransmitters from synapses
- replace damaged neurons
27
phagocytotic glial cell
**Microglia**
- smallest, least abundant CNS neuroglia
- engulfs invading microorganisms and dead neurons
- derived from monocytes
28
cuboidal, ciliated CNS neuroglia shown here as row of darker cells
**Ependymal Cell**
- line brain and spinal cord cavities
- produce **cerebrospinal fluid**
- ciliated to help circulate fluid
29
round central structure
**oligodendrocyte**
- CNS neuroglial cell with few branches
- one cell myelinates multiple axons of CNS
30
unlabeled structures surrounding the neuron body
**Satellite Cells**
- surround neuron bodies within ganglia of the PNS
31
Protective lipoprotein around axons
Myelin
- 20% protein, 80% lipid
- forms **myelin sheath**, concentric layers of plasma membrane of supporting cells (Schwann in PNS, Oligodendrocytes in CNS)
- insulates axon and increases speed of conduction
32
cytoplasm within the axon of a neuron
Axoplasm
33
Plasma membrane of an axon
Axolemma
34
Outermost layer of Schwann cells around axons
Neurilemma
- outermost layer where nucleus of Schwann cell resides
35
Unmyelinated Neurons
- thick axons are myelinated
- thin axons are unmyelinated, meaning surrounded and supported by Schwann cells, but not wrapped
36
What kind of neuron?
**Multipolar**
- more than 2 processes, many dendrites & 1 axon
- muscle innervation
37
What kind of neuron?
**Bipolar**
- 2 processes, dendrites on one, axon on other
- rare neurons in sensory organs (ex: retina)
38
What kind of neuron?
**unipolar neuron**
- pseudounipolar
- has one short single process connecting the body to the receptive and transmissive endings of the axon
39
Function Classification of Neurons
1. **Sensory (afferent) Neurons** - detect changes in body and environment
2. **Motor (efferent) Neurons** - send signals to muscles and glands (effectors)
3. **Interneurons (association neurons)** - between sensory and motor (CNS only), make up 99% of neurons, process, store and retrieve info
40
CT around each nerve fiber (axon)
Endoneurium
41
dense irregular CT around each nerve fascicle
Perineurium
42
dense irregular CT around entire nerve, binding fascicles
epineurium
43
nerve fascicles
a group of nerve fibers (axons) bound into bundles, surrounded by perineurium
44
sites at which neurons communicate
synapse
- signals pass in one direction only
45
cell that conducts a signal toward a synapse
presynaptic neuron
46
cell that transmits a signal away from a synapse
postsynaptic neuron
47
types of synapses
**Axosomatic** - axon to cell body
**Axodendritic** - axon to dendrites
**Axoaxonic** - axon to axon, signal acts on axon terminals only, regulating synapse function
48
functional junction between a neuron and another cell in which communication is transmitted via ions passing through gap junctions
electrical synapse
49
junction between a neuron and another cell in which neurotransmitters carry a signal across a space between the cells
chemical synapse
50
mebrane-bound sacs in a presynaptic neuron that contain neurotransmitters
synaptic vesicles
51
space between the axon terminal of one neuron and the dendrites of another
synaptic cleft
52
neuronal regeneration overview
- None in CNS
- Axons regenerate slowly (1-5 mm/day) in PNS, but not cell bodies
Dependent on:
* extent of damage
* Schwann cells' secretion of _Nerve Growth Factor_
* distance from damage to organ being innervated (closer = better)
53
Neuronal Regeneration Steps
1. axon is severed
2. proximal end of severed axon seals off/swells, distal end degenerates
3. distal Schwann cells form "regeneration tube"
4. axon regenerates and threads through tube
5. effector is reinnervated
54
Rapid, autonomic motor response to stimuli
Reflex
- predictable and involuntary
55
A simple chain of neurons responsible for a reflex
reflex arc
- made up of:
* **Receptor** - takes in stimulus
* **Sensory neuron** - transmits afferent signal
* **Integration Center** - 1+ synapses in CNS
* **Motor neuron** - conducts efferent signal
* **Effector** - muscle/gland which acts
56
Two Types of Reflexes
**Monosynaptic Reflex:**
* fastest
* contains no CNS interneurons
* less common
**Polysynaptic Reflex:**
* most common
* contains at least 1 CNS interneuron
Z Old Anatomy
flashcards
Decks in class (21)
# Cards
-
Tissues63
-
Integumentary System47
-
Bones & Skeletal Tissues67
-
Joints62
-
Muscular System61
-
Selected Skeletal Muscles52
-
Nervous System56
-
The Brain100
-
spinal cord37
-
Peripheral Nervous System44
-
Autonomic Nervous System23
-
Special Senses111
-
Endocrine System76
-
Cardiovascular Part I: Blood34
-
Cardiovascular Part II: Heart66
-
Cardiovascular Part III: Blood Vessels97
-
Lymphatic System44
-
Respiratory System89
-
Digestive System137
-
Urinary System72
-
Reproductive System77
