Ch. 9 Nervous System Flashcards
1
Q
Major aspects of nervous system:
A
- Sensory input
- Integration and processing (decision-making)
- Motor output (response)
2
Q
Functions of the nervous system:
A
- Thinking
- Movement
- Internal processes of physiology
3
Q
Main cell types in the nervous system:
A
- Neurons: (Functional unit) Cells that communicate, via electrical impulses, with other neurons or other tissues
- Neuroglia: (Supportive tissue) Cells that support, nourish, protect, and insulate neurons
4
Q
Neurons:
A
(Functional unit) Cells that communicate, via electrical impulses, with other neurons or other tissues
5
Q
Neuroglia:
A
(Supportive tissue) Cells that support, nourish, protect, and insulate neurons
6
Q
Neurotransmitters:
A
The chemical messengers in a synapse, that convey an electrical impulse from a neuron to another cell
- [Synapse: The space between two neurons]
7
Q
General functions of the nervous system:
A
- Sensory
- Integrative
- Motor
8
Q
Organs of the nervous system can be divided into 2 groups:
A
- Central nervous system (CNS):
- Made up of the brain and spinal cord
- Responsible for integration of information and decision-making - Peripheral nervous system (PNS):
- Made up of cranial and spinal nerves that connect the CNS to the rest of the body
- Contains sensory (afferent) and motor (efferent) divisions.- Motor functions:
- Somatic nervous system: controls voluntary skeletal muscles
- Autonomic nervous system: controls involuntary effectors (smooth and cardiac muscles and glands)
- Motor functions:
9
Q
Central nervous system (CNS):
A
- Made up of the brain and spinal cord
- Responsible for integration of information and decision-making
10
Q
Peripheral nervous system (PNS):
A
- Made up of cranial and spinal nerves that connect the CNS to the rest of the body
- Contains sensory (afferent) and motor (efferent) divisions.
- Motor functions:
- Somatic nervous system: controls voluntary skeletal muscles
- Autonomic nervous system: controls involuntary effectors (smooth and cardiac muscles and glands)
- Motor functions:
11
Q
Peripheral nervous system (PNS): Motor functions:
A
- Somatic nervous system: controls voluntary skeletal muscles
- Autonomic nervous system: controls involuntary effectors (smooth and cardiac muscles and glands)
12
Q
Somatic nervous system: (PNS)
A
Controls voluntary skeletal muscles
13
Q
Autonomic nervous system: (PNS)
A
Controls involuntary effectors (smooth and cardiac muscles and glands)
14
Q
Neuron (Nerve Cell) Structure:
A
- A neuron contains a cell body, tubular cytoplasm-filled dendrites, and a tubular, cytoplasm-filled axon.
- The cell body (soma) contains mitochondria, lysosomes, a Golgi apparatus, chromatophilic substance (Nissl bodies – similar to rough ER), neurofilaments, and a large nucleus with a nucleolus
- Dendrites conduct impulses toward the cell body; they are short and branching, and they provide the receptive surface for communication with other neurons
- The axon conducts impulses away from the cell body; it arises from a thickening extending from the cell body, called the axon hillock
- There is only 1 axon in each neuron
15
Q
Neuroglia (glial cells, “nerve glue”) are cells that..
A
Support neurons
16
Q
Functions of neuroglia:
A
- Fill spaces
- Support
- Protect
- Nourish
- Insulate
17
Q
Neuroglia..
A
Do not generate or conduct nerve impulses
- Because it is not a functional tissue
- [Parenchyma: Functional tissue]
18
Q
Central nervous system neuroglia:
A
- (1) Microglia: small cells that function as phagocytes for bacterial cells
and cellular debris, and produce scar tissue in sites of injury - (2) Oligodendrocytes: form the myelin sheath around axons in the brain and spinal cord
- (3) Ependymal cells: produce cerebrospinal fluid in CNS
- (4) Astrocytes: lie between blood vessels and neurons
- Functions:
- Structural support
- Regulation of nutrient and ion concentrations
- Formation of the blood-brain barrier, which protects brain tissue from chemical fluctuation and prevents entry of many substances
19
Q
Peripheral nervous system neuroglia:
A
- (1) Schwann cells: the myelin-producing neuroglia of the PNS
- (2) Satellite cells: provide protective coating around cell bodies of neurons in the PNS
20
Q
Meninges
A
- The brain and spinal cord are surrounded by 3 membranes called meninges that lie between the skull bones & vertebrae and the soft CNS tissues
- [Meninges: The 3 membranes of the central nervous system]
- The structures of the CNS: Brain and spinal cord
- [Meninges: The 3 membranes of the central nervous system]
- The meninges consist of the dura mater, arachnoid mater, and pia mater:
- Dura mater
- (Line the skull bone)
- Outermost layer of meninges
- Made up of tough, dense connective tissue, and is very thick
- Contains many blood vessels
- Forms the internal periosteum of the skull bones
- In some areas, the dura mater forms partitions between lobes of the brain, and in others, it forms dural sinuses
- The sheath around the spinal cord is separated from the vertebrae by an epidural space - Arachnoid mater
- The middle layer of meninges
- Thin, weblike layer that lacks blood vessels
- Between the arachnoid and pia mater is the subarachnoid space, which contains cerebrospinal fluid (CSF)
- [Subarachnoid space: Space below the arachnoid mater and above the pia mater, containing cerebrospinal fluid (CSF)] - Pia mater
- (Covers the brain and spinal cord)
- The innermost layer of the meninges
- Thin layer, which contains many blood vessels and nerves
- Attached to the surface of the brain and spinal cord, and follows their contours
21
Q
The meninges consist of the
A
Dura mater, arachnoid mater, and pia mater:
22
Q
Dura mater
A
- (Line the skull bone)
- Outermost layer of meninges which forms the internal periosteum of skull bones
- Made up of thick, tough, and dense connective tissue, containing many blood vessels
- In some areas, the dura mater forms partitions between lobes of the brain, and in others, it forms dural sinuses
- [Epidural space: Space between skull and dura mater]
23
Q
Arachnoid mater
A
- The middle layer of meninges
- Thin, weblike layer that lacks blood vessels
- Between the arachnoid and pia mater is the subarachnoid space, which contains cerebrospinal fluid (CSF)
- [Subarachnoid space: Space below the arachnoid mater and above the pia mater, containing cerebrospinal fluid (CSF)]
24
Q
Pia mater
A
- (Covers the brain and spinal cord) and follows their contours
- The innermost layer of the meninges
- Thin layer, which contains many blood vessels and nerves
25
Q
Spinal cord:
A
- Begins at the base of the brain at the foramen magnum
- [Foramen magnum: A large hole in the occipital bone] - Extends as a thin cord to the level of the intervertebral disc between the 1st and 2nd lumbar vertebrae
- Total of 5 lumbar vertebrae
26
Q
Cervical enlargement:
A
- A thickened area near top of spinal cord
- Provides nerves to upper limbs
27
Q
Lumbar enlargement:
A
- A thickened region near the bottom of the spinal cord
- Gives rise to nerves that serve the lower limbs
28
Q
Cauda equina (horse’s tail/pony-tail):
A
- Structure formed where spinal cord tapers to a point inferiorly
- Consists of spinal nerves in the lumbar & sacral areas
29
Q
The Brain
A
- Largest part of the nervous system
- The brain is the largest, most complex portion of the nervous system, containing 100 billion multipolar neurons, and many neuroglia to support the neurons
- Structure is reversed from that of spinal cord; gray matter outside and white matter inside
- The 4 main parts of the brain:
- (1) Cerebrum: Largest portion; associated with higher mental functions, and sensory & motor functions
- Can be divided into 4 lobes:
- (1) Frontal
- (2) Parietal
- (3) Temporal
- (4) Occipital
- Can be divided into 4 lobes:
- (2) Diencephalon: Processes sensory input and controls many homeostatic processes
- 3 Areas consist of:
- (1) Thalamus
- (2) Hypothalamus
- (3) Pituitary gland
- 3 Areas consist of:
- (3) Cerebellum: Coordinates muscular activity
- Below the occipital lobe
- (4) Brainstem: Coordinates and regulates visceral activities, and connects different parts of the nervous system
- Passes through the foramen magnum, and becomes the spinal cord
- (1) Cerebrum: Largest portion; associated with higher mental functions, and sensory & motor functions
30
Q
The 4 main parts of the brain:
A
- (1) Cerebrum: Largest portion; associated with higher mental functions, and sensory & motor functions
- Can be divided into 4 lobes:
- (1) Frontal
- (2) Parietal
- (3) Temporal
- (4) Occipital - (2) Diencephalon: Processes sensory input and controls many homeostatic processes
- 3 Areas consist of:
- (1) Thalamus
- (2) Hypothalamus
- (3) Pituitary gland - (3) Cerebellum: Coordinates muscular activity
- Below the occipital lobe - (4) Brainstem: Coordinates and regulates visceral activities, and connects different parts of the nervous system
- Passes through the foramen magnum, and becomes the spinal cord
31
Q
Structure of the cerebrum:
A
- Cerebrum is largest portion of the mature brain
- Consists of 2 cerebral hemispheres (Right and left), which are mirror images and divided by a longitudinal fissure: the corpus callosum
- Those who are right handed, there left hemisphere is active
- Those who are left handed, there right hemisphere is active - Corpus callosum: (Longitudinal fissure) flat bundle of nerve fibers that connects the hemispheres
- The surface of the brain is marked by these features:
- Gyri (singular is gyrus): (Elevation) Ridges
- Sulci (singular is sulcus): (Depression) Grooves
- Fissures (longitudinal and transverse): deep grooves
- Four lobes of the cerebrum are named according to the bones they underlie: frontal, parietal, temporal, and occipital lobes
32
Q
Corpus callosum:
A
(Longitudinal fissure) flat bundle of nerve fibers that connects the hemispheres
[- Consists of 2 cerebral hemispheres (Right and left), which are mirror images and divided by a longitudinal fissure: the corpus callosum
- Those who are right handed, there left hemisphere is active
- Those who are left handed, there right hemisphere is active
33
Q
The surface of the brain is marked by these features:
A
- Gyri (singular is gyrus): (Elevation) Ridges
- Sulci (singular is sulcus): (Depression) Grooves
- Fissures (longitudinal and transverse): deep grooves
- Four lobes of the cerebrum are named according to the bones they underlie: frontal, parietal, temporal, and occipital lobes
34
Q
Functions of the cerebrum:
A
- The cerebrum provides higher brain functions:
- Interpretation of sensory input
- Initiating voluntary muscular movements
- Stores information for memory
- Integrates information for reasoning
- Intelligence
- Personality
35
Q
Cerebrum:
A
Largest portion; associated with higher mental functions, and sensory & motor functions
- Can be divided into 4 lobes:
- (1) Frontal
- (2) Parietal
- (3) Temporal
- (4) Occipital
36
Q
Diencephalon:
A
Processes sensory input and controls many homeostatic processes
- 3 Areas consist of:
- (1) Thalamus
- (2) Hypothalamus
- (3) Pituitary gland
37
Q
Cerebellum:
A
Coordinates muscular activity
- Below the occipital lobe
38
Q
Brainstem:
A
Coordinates and regulates visceral activities, and connects different parts of the nervous system
- Passes through the foramen magnum, and becomes the spinal cord
39
Q
Ventricles and cerebrospinal fluid:
A
- Ventricles: a series of connected cavities within the cerebral hemispheres and brainstem
- Continuous with central canal of spinal cord and subarachnoid space; all of these cavities are filled with cerebrospinal fluid (CSF)
40
Q
Flow of CSF proceeds through the ventricles and channels in this order:
A
- 2 Lateral ventricles— Connected to the 3rd ventricles by the: Interventricular foramina
- Third ventricle— Connected to the 4th ventricle by the: Cerebral aqueduct
- Fourth ventricle, which is continuous with the central canal of the spinal cord and the subarachnoid space of the meninges
41
Q
Any fluid in the body is called:
A
Filtration of blood
- EX: Urine, CSF
42
Q
Choroid plexuses:
A
- (Ball of capillaries which filter blood to form CSF)
- Masses containing specialized capillaries from the pia mater
- Found in all 4 ventricles
- Secrete cerebrospinal fluid (CSF) into the ventricles; most CSF arises in the lateral ventricles
- CSF circulates through ventricles and connecting passageways into the subarachnoid space, where it is reabsorbed back into the blood
- CSF completely surrounds brain and spinal cord
- CSF has nutritive as well as protective (cushioning) functions
43
Q
Hydrocephalus:
A
- When the ventricle gets overflowed with fluid (Collection of CSF in the ventricle), CSF caused a blockage to the flow causing hydrocephalus
- Abnormal buildup of cerebrospinal fluid in the ventricles (cavities) deep within the brain. This excess fluid causes the ventricles to widen, putting harmful pressure on the brain’s tissues
- [Hydrocephalus: CSF overflow causing a clogged blockage to in the ventricle]
44
Q
Parts of the diencephalon:
A
- Thalamus
- Hypothalamus
- Pituitary gland
45
Q
Functions of the thalamus:
A
- Sorting and directing sensory information arriving from other parts of the nervous system to the cerebral cortex
- Channels all sensory impulses, except those for the sense of smell
- Produces general awareness of the sensation, such as pain, touch and temperature
46
Q
Functions of the hypothalamus
A
- The hypothalamus maintains homeostasis by regulating a wide variety of visceral activities, and by linking the endocrine system with the nervous system:
- Regulates heart rate and arterial blood pressure
- Regulates body temperature, water and electrolyte balance,hunger and body weight
- Controls movements and secretions of the digestive tract
- Helps to regulate sleep and wakefulness
- Stimulates the posterior pituitary gland to secrete stored hormones
- Produces hormones that cause the anterior pituitary gland to secrete its hormones
47
Q
The brainstem consists of:
A
- Midbrain
- Pons
- Medulla oblongata
- Lies at the base of the cerebrum
- Connects the cerebrum, diencephalon, and cerebellum to the spinal cord
48
Q
The cerebellum:
A
- The cerebellum is located beneath the occipital lobes of the cerebrum, posterior to the brainstem
- Made up of 2 hemispheres connected by the vermis
- A thin layer of gray matter called the cerebellar cortex lies outside a core of white matter called the arbor vitae
- The cerebellum communicates with other parts of the central nervous system through 3 pairs of tracts, the cerebellar peduncles
49
Q
Functions of cerebellum:
A
- Integrates sensory information about the position of body parts
- Coordinates skeletal muscle activity
- Maintains posture
- Ensures that movement occurs in the desired manner
50
Q
Peripheral Nervous System (PNS)
A
- Consists of nerves that connect the CNS to body parts
- Consists of cranial nerves, arising from the brain, and spinal
nerves, arising from the spinal cord - Contains sensory and motor divisions
- The motor part of the PNS is made up of 2 portions:
- Somatic nervous system, which connects the CNS to skeletal muscles and the skin, and oversees conscious activities
- Autonomic nervous system, which connects the CNS to viscera, and controls subconscious activities
51
Q
Subdivisions of the Nervous System: RECAP
A
- Central nervous system (CNS)
1. Brain
2. Spinal cord- Peripheral nervous system (PNS)
- Cranial nerves arising from the brain and brainstem
- Sensory fibers connecting peripheral sensory receptors
to the CNS - Somatic fibers connecting to skin and skeletal muscles
- Autonomic fibers connecting to viscera
- Sensory fibers connecting peripheral sensory receptors
- Spinal nerves arising from the spinal cord
- Sensory fibers connecting peripheral sensory receptors
to the CNS - Somatic fibers connecting to skin and skeletal muscles
- Autonomic fibers connecting to viscera
- Sensory fibers connecting peripheral sensory receptors
- Cranial nerves arising from the brain and brainstem
- Peripheral nervous system (PNS)
52
Q
Cranial nerves:
A
- Twelve pairs of cranial nerves arise from the underside of the
brain - Most are mixed nerves, containing sensory & motor nerve fibers, but some are only sensory, and others are primarily motor
- The first pair arises from the cerebrum, and the second pair from the thalamus, but most arise from the brainstem
- The 12 pairs are designated by number and name; the numbers are in order, from superior to inferior
53
Q
Nerve X: Vagus (Type and function)
A
- Type: Mixed
- Functions:
- Somatic motor fibers conduct impulses to muscles associated with speech and swallowing; autonomic motor fibers conduct impulses to the heart, smooth muscle, and glands in the thorax and abdomen
- Sensory fibers conduct impulses from the pharynx, larynx, esophagus, and viscera of the thorax and abdomen
54
Q
Spinal nerves:
A
- 31 pairs of spinal nerves arise from spinal cord
- All except the first pair are mixed nerves
- Grouped according to the level from which they arise
- Numbered in sequence: 8 pairs of cervical nerves, 12 pairs of thoracic nerves, 5 pairs of lumbar nerves, 5 pairs of sacral nerves and 1 pair of coccygeal nerves
- Each arises from two roots: a sensory dorsal root, and a motor ventral root
- Each dorsal root contains a dorsal root ganglion, which houses the cell bodies of sensory neurons entering the spinal cord
- A ventral root and dorsal root unite to form a spinal nerve, which extends out of the vertebral canal through the intervertebral foramen
55
Q
Spinal nerve plexuses: The main branches of spinal nerves, except in the thoracic region, form networks called plexuses
A
- Cervical Plexuses (C1-C4):
- Lie on either side of the neck; supply muscles and skin of the neck; include the phrenic nerves, which control the diaphragm - Brachial Plexuses (C5 – T1):
- Arise from lower cervical and upper thoracic nerves; supply muscles and skin of arms, forearms, and hands; lead into the upper limbs; include the musculocutaneous, ulnar, median, radial, and axillary nerves - Lumbosacral Plexuses (L1-S4):
- Arise from the lower spinal cord; supply muscles and skin of the lower abdomen, external genitalia, buttocks, and legs; include the obturator, femoral, and sciatic nerves - Anterior branches of the thoracic spinal nerves do not form plexuses, but become the intercostal nerves.
