Nervous System Flashcards
1
Q
Functions of the NS
A
- Sensory: Sense changes through sensory receptors that deviate from homeostasis
- Motor: Responde to stimuli as sensory information comes in
- Integrative: Analyze incoming sensory information, store some aspects (higher level processing of separating info), and make decisions regarding appropriate behaviours.
2
Q
What components are part of the NS
A
- Brain
- Spinal cord
- Nerves
- Sensory receptors
3
Q
Subdivisions
A
- Central nervous system (CNS): Brain and spinal cord
- Peripheral nervous system (PNS): Sesnory receptors and nerves
4
Q
Sensory receptors
Components of the PNS
A
- Ending of neurons or separate, specialized cells that detech things like temperature, pain, etc.
5
Q
Nerve
A
- A bundle of axons and their sheaths that connects the CNS to sensory receptors, muscles, and glands
1. Cranial nerves: Originate from the brain; 12 pairs
2. Spinal nerves: Originate from the spinal cord; 31 pairs
6
Q
Ganglion
A
- Collection of neuron cell bodies outside the CNS
- The sensory information from spinal nerves have their neuron cell bodies in ganglions
7
Q
Plexus
A
- Extensive network of axons, and sometimes neuron cell bodies located outside CNS
8
Q
Divisions of the PNS
A
- Sensory (afferent): Transmits action potential from receptors to CNS
- Takes the information from external environment via sensory receptors and beings it back to the CNS for processing. - Motor (efferent): Transmits action potention from CNS t othe effectors (muscles, glands etc.)
- Somatic or autonomic pathway with further subdivisions.
9
Q
Sensory Division of PNS
A
- Gathers information form external and internal environments
1. General senses: receptors spread thorughout the body (to feel temp, pressure)
2. Special senses: Receptors in specific organs (vision, hearining etc.)
SIDE NOTE: If we look at the spinal cord, doral part carries sensory information, while the front carries motor information.
10
Q
Somatic nervous system
Motor division of PNS
A
- Part of motor division
- CNS to skeletal muscles
- Voluntary control
- Single neuron system, where just the axon is going to the targe tissue.
- Synapse at the skeletal muscle occurs at the junction of a nerve cell with another cell. Neuromuscular junction is a synapse between a neuron and skeletal muscle cell.
- Once signal oes out, a contaction occurs.
11
Q
Automonic nervous system (ANS)
A
- From the CNS to smooth muscles, cardiac muscle and certain glands
- Involuntary control
- Two neuron system: first from the CNS to the ganglion; second from the ganglion to the effector
- Further division of the ANS include symapthetic and parasympathetic
12
Q
Symapthetic
A
- Prepares body for physical activity (fight or flight)
- Increase heart rate…goes from resting to active
13
Q
Parasymapthetic
A
- Regulates resting or vegetative functions such as digestion (rest and digest)
14
Q
Enertic nervious system (ENS)
A
- Plexuses within the wall of the digestive tract.
- Can control the digestive tract independently of the CNS, but still communicate with the CNS via the ANS (parasympathetic and sympathetic neurons contribute to the plexus)
Sensory: Monitor chemical and enviornmental and stretching of wall
Motor: Contracts smooth muscle and control secretions of GI organs and endocrine walls.
15
Q
Cells of Nervous System (brief)
A
- Neurons or nerve cells receive stimuli and transmit action potential via cell bodies, denderites, and axons
- Neuroglia or glial cells are non neural cells (cannot generate action potential), they support and protect neurons
16
Q
Neurons
A
Recieve stimuli and transmit singlas to other neurons or effector organs
17
Q
Dendrites
A
Short, extensions of the cell body that can interact with other axons of neurons
18
Q
Axon
A
- Arise from the cone shaped axon hillock, at a section called the litial segment…together they form the trigger zone where action potential signal is created.
- Cytoplasm = axoplasm; membrane = axolemma
- Terminal end contains the presynapitic terminal or synapic end bulb.
- Collateral axons allow branching of action potential to different regions
19
Q
Axonal transport
A
- Vesicles carry neurotransmitters in the presynaptic termial
- They release neurotransmitters to stimulate or inhibit postsynaptic cell.
- Vesicles can move up and down the axon transporting neurotransmitters, but this is also a way for diease to spread to the CNS
20
Q
Functional classifications
A
Sensory or afferent: Action potential towards CNS
Motor or efferent: Action potential away from CNS
Interneurons or association neurons: Within CNS from one neuron to another.
21
Q
Strucuture classification
A
- Multipolar: many dendrites, single axon; most neurons in the CNS and motor neurons
- Bipolar: 1 dendrite, 1 axon; sensory organs
- Unipolar: Single process extending from cell body; divides into two branches; part extending to periphery has dendrites that typically function as sensory receptor (found in peripheral receptors for touch, temp, pain)
22
Q
Neuroglia
A
- Acts as nerve glue, aka glial cells
- Numerous, amount >50% of the weight of the brain
- 4 types of neuroglial cells in the CNS
- 2 types in the PNS
- Unique structure and function
23
Q
Astrocytes
A
- Star shaped
- Cytoplasmic extension branch to form foot processes which cover the surface of blood vessels, neurons, pia mater
- Release chemical to form tight junctions between endothelial cells of capillaries
- Suppports cells in the CNS
- Astrocyte foot processes envelop blood vessels in the brain and spinal cord, playing a key role in maintaining the blood-brain barrier and regulating blood flow.
- Astrocytes release signaling molecules that act on the endothelial cells of the blood-brain barrier. These molecules promote the formation of tight junctions between the endothelial cells that line the capillaries in the brain. These tight junctions prevent the passage of large molecules and potential toxins from the bloodstream into the brain, while allowing essential nutrients to pass through.
24
Q
Ependymal cells
A
- Line the ventricles of the brain and central canal of the spinal cord (CNS)
- Helps form the choroid plexus which produces CSF
- Patches contain cilia which helps move CSF through ventricle.
- Come in a variety of shapes
25
Q
Microglia
A
- Specialized macrophages in the CNS that protect CNS from invaders
- Phagocytic on dying tissue, microorganisms, foreign substances that invade the CNS
26
Q
Oligondendrocytes
A
- Cytoplasmic extensions that surround axons
- Wraps around the axon multiple times in the CNS
- Form myelin sheaths around portions of several axons
27
Q
Schwann Cells
A
- Wraps around axons
- Forms myelin sheath around a portion of only one axon
- Supports cells in the PNS
28
Q
Satellite cells
A
- Surrounds neurons cell bodies in ganglia
- Provides nutrients to cell body
29
Q
Myelinated vs Unmyelinated Axons
A
Myelin - protect and insulates axons from one another
Myelinated - axons conduct signals more rapidly
30
Q
Tracts
A
Bundle of myelinated axons in the CNS
31
Q
Nucleus
A
- Collection of neuron cell bodies in the CNS
32
Q
White matter
A
- Myelinated axons.
- Nerve tracts propagate action potential from one area in the CNS to another
- Lipid looks white
33
Q
Grey matter
A
- Unmyelinated axon, cell bodies, dendrites, neuroglia.
- Used for integrative functions
34
Q
Grey vs. white matter
A
- Spinal cord contains white matter on the outside and gray matter on the inside
- Brain has greay matter on the outside cortex and inner nuclei, and white matter deeper in the brain.
