Module 12: Nervous System (a) Flashcards
1
Q
Central Nervous System
-Components
A
- Brain
- Spinal Cord
- CSF — CSF surrounds the brain and spinal cord for protection
- BBB — The blood brain barrier separates and shields the CNS from the body’s periphery
2
Q
CNS
-Major Structures in the Brain
A
- Forebrain (Prosencephalon)
- Telecephalon
- Diencephalon — Interbrain - Midbrain (Mesencephalon) — Connects the pons to the diencephalon and includes the:
- corpora quadrigemina
- tegmentum
- Cerebral peduncles
- Connects the forebrain and the hindbrain
- Tectum is involved w/ voluntary and involuntary motor movements
- Flood of the midbrain contains the RED NUCLEUS and the SUBSTANTIA NIGRA - Hindbrain (Rhombencephalon)
- Cerebellum
- Pons
- Medulla
3
Q
CNS
-Spinal Cord
A
- Long nerve that connects the brain and body
2. Continues from the Medulla oblongata and ends between the first and second lumbar vertebrae
4
Q
PNS
-Components
A
- 12 Cranial Nerves
- 31 spinal nerves
- Somatic
- Afferent (Sensory) — Ascending pathways — Carry Impulses from PNS to CNS
- Efferent (Motor) — Descending pathways — Carry impulses from CNS to target organs like skeletal muscle - Autonomic
- Sympathetic
- Parasympathetic
5
Q
Nervous System
-Cell Types (2)
A
- Neurons
2. Neuroglia — Support the neurons of the CNS
6
Q
Nervous System Cells
-Neurons
A
- Generates and transferes nerve impulses
- Specialized cells and do not need insulin to take up glucose**
3 components
- Cell body - Located in the CNS — Cell bodies in the PNS are called ganglia
- Dendrites - Receptor portion of the neuron — Carries nerve impulses toward cell body
- Axons - carry nerve impulses AWAY from cell body — Typical neuron has 1 axon wrapped in myelin sheath — made of Schwann cells
7
Q
Nervous System Cells
-Neuroglia Cells
A
- 2 Types of Myelinating Cells
- Oligodendroglia — Form Myelin sheath around axons in the brain and spinal cord
- Schwann Cells — Form Myelin sheath around axons in the PNS - Non-Myelinating Schwann Cells
- Provide metabolic support (Ex: astrocytes which are essencial components of BBB) —
- Micróglia — Remove cellular debris - Nodes of Ranvier — Where tight Schwann cells are pinched to create gaps — Improves speed of conduction of nerve impulse
8
Q
Neurotransmitters
-Examples of substances
A
- Amino acids — GABA, Glyceine, Glutamate, aspartate
- Neuropeptídes — Endorphins
- Monoamines — Nor-epinephrine, serotonin, dopamine & histamine
9
Q
Neurotransmitters
-Summation Definition
A
- Brings membrane closer to Threshold potential
10
Q
Forebrain Functions
-Telencephalon
A
- The telencephalon consists of
- Cerebral cortex
- Basal Ganglia - The Cerebrum makes up the forebrain — Divided into right and left hemispheres by the longitudinal fissure
- Cerebral cortex — Outer layer of the cerebrum and is made up of gray matter
- White matter lies beneath the cortex and contains myelinated axons - The Cortex can be further divided into functional lobes:
11
Q
Forebrain Functions
-Telencephalon Functional Lobes
A
- The Frontal Lobe
- Prefrontal area — Responsible for Goal-directed behavior, Short term memory, complex thought
- The rest of the frontal lobe coordinates motor movements
- Broca’s area — Speech and language interpretation — Motor speech — Inferior portion of frontal lobe - Parietal lobe — Somatic Sensory input
- Occipital lobe — Visual cortex which receives input from the retinas
- Temporal lobe — Primary auditory cortex, equilibrium, emotion, & memory
- WERNICKE’s area —Speech and language interpretation — Speech interpretation - Limbic Structures — Control emotions, short-term memory
- Nuclei of the basal ganglia — Masses of gray matter that are involved in the initiation and planning of learned motor activities.
12
Q
Forebrain Functions
-Diencephalon
A
Second part of the forebrain and is the land of THALMUS
- Epithalmus — Pineal body — secretes melatonin
- THALMUS — Relays motor and sensory signals to the cortex — Integrates afferent impulses and interprets info such as auditory, visual, tactile and taste
- Hypothalamus — Responsible for Maintenence of the internal environment - Regulates autonomic nervous system Ex: body temp,endocrine function, emotional expression and control of the pituitary gland
- Subthalamus — Part of the basal ganglia and connects to the substantia nigra of the midbrain
—Subthalmus plays large role in extrapyramidal system which is important for FINE MOTOR MOVEMENT
13
Q
Forebrain Functions
-Limbic System
A
1. Consists of an arc of structures between the telencephalon and the diencephalon Structures include the -Amygdala -Hippocampus -Fórnix -Hypothalamus -Autonomic Nuclei
- Limbic system function — Involvement in primitive behavioral responses such as emotion, fear, anger, pleasure, feeding, biological rhythms and sense of smell
14
Q
Midbrain
-Components
A
- Tectum — Visual & Auditory motor movements
- Tegmentum
- Red Nucleus — Receives sensory information from the cerebellum and sends it to the cervical spinal cord
- Substantia nigra — Synthesizes dopamine - Cerebral Peduncles — Contain white matter tracts that contain EFFERENT nerves that relay signals between cortex and brain stem
15
Q
Hindbrain
-Components
A
- Cerebellum — Responsible for regulation & coordination of movement, posture, and balance — Finger nose or heel shin test
- Controls conscious and unconscious muscle synergy required for maintaining balance and posture
- Does not initiate movement, just helps coordinate it - Pons — Transmits information from cerebellum to the brainstem
- Important for the control of RESPIRATION**
- Nuclei of the 5th and 8th cranial nerves are located in the pons - Medulla Oblongata — lowest portion of the brainstem and is responsible for various reflex activities
—Ex: Heart rate, respiration, BP, coughing, sneezing, swallowing, vomiting
16
Q
Protective Structures of the Brain
A
- Dura matter — Rigid double thickness membrane
- Arachnoid — spongy membrane under the dura
- Pia Matter — delicate membrane closely adhering to brain and spinal chord surface providing support for vessels
17
Q
Vertebral Column
A
- Cervical - 7
- Thoracic - 12
- Lumbar - 5
- Sacral - 5 fused
- Coccygeal - 4 fused
18
Q
Spinal Cord
-Components
A
- Grey Matter — Forms the inner core and is the central part of the spinal cord
- White Matter — Contains spinal tracts
- Large bundles of nerves that carry information up and down spinal cord
- Some are ascending and descending
19
Q
Spinal Cord
-Grey Matter
A
- Posterior Horn — Back part of the wing of the gray matter/butterfly shape
- Receives information from receptors in skeletal muscles, organs, and glands - Anterior Horn — Containts nerve cell bodies for EFFERENT or motor pathways
20
Q
Reflexes
-Structures necessary to Elicit a Reflex?
A
- Receptor
- Afferent & Efferent neuron
- Effector muscle or gland
- Reflexes are usually perceived before the sensory event is processed in the brain TEST
21
Q
Blood Supply to the Brain
A
- Internal carotid and vertebral artery supply the brain w/ arterial blood
- Circle of Willis — 5 arteries come together to form a circle — helps provide opportunity for collateral or compensatory blood flow
- Blood Brain Barrier —Highly selective semi-permeable membrane that separates circulating blood from extracellular fluid in the CNS
-ASTROCYTES are Neuroglia that surround blood vessels in CNS to form BBB
-
22
Q
Cranial Nerves
-Info
A
- CN’s are myelinated w/ Schwann cells
- Groups of cell bodies in the PNS are ganglia — In the CNS they are called nuclei - PNS nerves have a sheath of connective tissue that provides protection and support
- PNS operates for both afferent and efferent functions
- CN’s are classified as peripheral nerves, but DO project to nuclei in the brain and brainstem
- Most nerves are Mixed (Sensory and motor)
23
Q
CN
-Sensory or Motor
A
- CN I, II, VIII are Sensory ONLY
- CN III, IV, VI & XI & XII are BOTH but primarily Motor
- The rest are Both
24
Q
Spinal Nerves
-Info
A
- The names of the spinal nerves correlate w/ the vertebral level from which they exit
- They are mixed sensory and motor nerves & arise from the anterior and posterior horns of the spinal cord
- These nerves travel from the spinal cord then merge into groupings referred to as Plexus
25
Q
Spinal Nerves
-Plexuses
A
- Cervical Plexus — Covers the diaphragm, neck and hyoid bone
- Brachial Plexus — Provides impulses to the arm
- Lumbar Plexus — Carries impulses from the hip, gluteus, thigh, foot and perineum
- Coccygeal Plexus — Correlates to the skin of the coccyx
26
Q
Spinal Nerves
-Dermatomes
A
- When sensory signals arise from a particular area o the body, these are known as dermatomes
- Important for assessing spinal compression and for diagnosing things like varicella zoster
27
Q
ANS
-Info
A
- The autonomic NS is what regulates most of the involuntary functions of our internal organs
- Components of the ANS are in the CNS and PNS
- Peripheral autonomic nerves carry mainly EFFERENT fibers, meaning motor function
- Consist of both myelinated and un-myelinated neurons - Myelinated neurons are known as Pre-Ganglionic **
- Un-myelinated neurons are known as POST-Ganglionic **
28
Q
ANS
-Sympathetic NS
A
- Mobilizes energy stores in times of need — FIGHT OR FLIGHT Response
- Receives Innervation signals from cell bodies located between T1 - L2 Known as Thoracolumbar division
- Ganglia of the SNS Deliver info to the body about stress and impending danger
- Adrenal Medulla releases Epinephrine and norepinephrine
- Epinephrine release from adrenal medulla causes increase glucose levels (glycogenolysis in liver), breakdown of adipose tissue and glycolysis in muscle tissue
- Nor-Epinephrine acts on alpha receptors which cause vasoconstriction and increase in Blood pressure
- Stimulation of beta receptors cause vasodilation and increased blood flow to muscles
29
Q
ANS
-Parasympathetic NS (PNS)
A
- Functions to conserve and restore energy — REST AND DIGEST
- Nerve cell bodies arise in the CNS — Receptor organs receive Innervation from cell bodies in the CN nuclei and sacral region of spinal cord
—This is known as the CRANIOSACRAL DIVISION - When PNS is activated
- Reduced HR, improved digestion, Increased peristalsis and relaxation of sphincters, CNS will cause pupillary constriction, tear secretion and salivation
- Parasympathetic fibers activate certain regions so the division has less widespread effect
30
Q
Neurotransmitters of the Autonomic NS
A
- Both Sympathetic and Parasympathetic pre-ganglionite fibers use Acetylcholine**
- In the Postgalnglionic fibers
- Parasympathetic fibers use acetylcholine
- Sympatetic postganglionic fibers use Nor-Epinephrine
31
Q
Asdf
A
Asdf
32
Q
Intervertebral Disks
-Structure
A
- Nucleus Palposus — Located in the middle of each disc — Mass of jelly like fibers that is mainly water — Helps with spinal mobility
- Annulus Fibrosis — Tough outer exterior that encircles the disk — Some people tear their annular fibrosis
