Anat Final The Nervous System Flashcards
The nervous system coordinates all body systems and includes (5)
Sensory receptors
Spinal cord
Brain
Effectors
Nerves
What are the two structural divisions of the nervous system
Central nervous system (CNS)
Peripheral nervous system (PNS)
CNS consists of
Brain
Spinal cord
PNS consists of
All nerves outside the CNS
cranial nerves
Spinal nerves
What are the two functional divisions of the PNS
Somatic nervous system
Autonomic nervous system
Somatic nervous system control and effectors?
Voluntary control (by conscious will)
Effectors: skeletal muscle
Autonomic nervous system control and effectors
Involuntary
Smooth cardiac muscle, cardiac muscle and glands
Autonomic nervous system 2 categories
Sympathetic
Parasympathetic
2 main cell types of nervous system
Neurons and Neuroglia
Neurons are the
Highly specialized functional cells of the nervous system
What are the 3 parts of neurons
Body
Dendrites
Axons
Dendrites carry impulses
To cell body
(Function as receptors)
Axons carry impulses
Away from cell body
(Delivers impulse to another neuron, muscle or gland
Sensory neurons conduct impulses to?
Afferent or efferent?
The spinal cord and brain
Afferent
Motor neurons carry impulses from?
Afferent or efferent?
The CNS to muscles and glands
Efferent
Interneurons: impulses are related
From place to place in CNS
(Reflexes, balance)
Nerves may contain
All sensory fibers, all motor fibers or a combo of both
Most of the cranial nerves and all the spinal nerves are
Mixed nerves (contain both sensory and motor)
Function of Neuroglia
Convey auxiliary functions for neurons (support, protection, repair, nourishment, waste disposal)
Neuroglia: Schwann cells (PNS) form
Myelin sheaths on axons in PNS only
What are the three main types of glial in CNS
Astrocytes
Oligodendrocytes
Microglia
Most tumours of the nervous tissue are ____ because?
Glial tumours because this tissue continues to multiply throughout life more frequently than neurons
The myelin sheath is a ?
What does it provide
Whitish, fatty substance covering some axons
Provides insulation and protection
PNS: myelin sheath =?
AIDS in the regeneration of?
Schwann cells
Damaged neurons
CNS: myelin sheath =?
Oligodendrocytes
CNS: Myelinated axons make up
White matter
CNS: unmyelinated axons make up
Gray matter
What are nodes
Tiny gaps/small spaces between the individual cells; nerve impulses jump to and from
Nodes speeds the?
Conduction of nerve impulses
Disorders of nervous tissue: multiple sclerosis (MS)
Characterized by myelin loss in central nerve fibers
(More common in women)
Neuroma
General term for nervous system tumours
Disorders of the nervous tissue: multiple neurofibromatosis
Numerous benign tumours (genetic)
Affects Schwann cells of skin
Neuron fibers are collected into ___ throughout the system
Bundles aka fascicles
Connective tissue layers (nervous system)
Endoneurium (around individual fibers)
Perineurium (around each fascicle)
Epineurium (around entire nerve)
Enclosed, cable-like bundle of axons in the PNS
Nerve
Bundle of nerve fibers within the CNS
Tract
Describe self propagating wave (unmyelinated)
action potential (AP) generated at each membrane segment
AP spreads continuously along cells membrane
Describe Saltatory conduction
Rapid conduction
Impulse jumped from node to node along a myelinated fiber
Myelin insulates the fiber against current
At resting state the plasma membrane is said to be
Polarized
(Negative electric charge; negative membrane potential)
What produces and maintains charge differences between inside and outside of cell using sodium-potassium pumps
Active transport
Resting state: Sodium ions are more concentrated where
Outside the cell
Resting state: potassium ions are more concentrated where
Inside the cell
During rising phase/depolarization (nerve impulse) inward movement of ___ depolarizes the membrane
Na (sodium)
During the Repolarization/falling phase what leaves the cell
K+ (Potassium)
At the point of Repolarization/falling phase what does not happen? What does this cause?
Does not respond to other stimuli
Causes AP to move in one direction from point of stimuli
What is a synapse
Junction point for transmitting the nerve impulse from neuron to another cell
What is synaptic cleft
Gap between the cells
What is Presynaptic cell
Axon of cell transmitting impulse
What is the chemical released from vesicles at end of axon that enables a nerve omits to cross a synaptic cleft
Neurotransmitters
What is a Postsynaptic cell
Dendrite of another cell receiving impulse and neurotransmitter
Postsynaptic cell binds neurotransmitters via
Receptors
What influences how or if the cell will respond to the neurotransmitter
Receptors
Examples of neurotransmitters
Norepinephrine
Serotonin
Dopamine
Acetylcholine
Some neurotransmitters act to ____ the postsynaptic cell and keep it from ____
Inhibit; reacting
May play a role in sleep, motor function, mood, and pleasure recognition
Catecholamines
What are natural painkillers; two morphine like neurotransmitters
Endorphins and enkephalins
The cells response is based on the total effects of ______ it receives at any one time
All the neurotransmitters
What disease is characterized by low levels of dopamine
Parkinson’s
What is the pathway of a reflex arc
Receptor to sensory neuron to interneuron (CNS) to motor neuron to effector
What is a simple reflex
Rapid, uncomplicated and automatic response involving only two types of neurons (sensory with motor)
What is a stretch reflex
Contraction of a stretched muscle after a stimulus
What is a spinal reflex
Simple reflex that passes through the spinal cord alone
(Does not involve the brain)
Knee jerk relfex consists of
Simple reflex and stretch reflex
The spinal cord links the
PNS and the brain
End of spinal cord is a fan of nerves called
Cauda equina
Ascending tract of the spinal cord carries sensory impulses from
Spinal cord to brain
Descending tract of spinal cord carries motor impulses from
Brain to PNS
All spinal nerves are ?
* hint contain both sensory and motor fibers
Mixed nerves
The spinal nerves conduct impulses between
The spinal cord and parts of the body not supplied by cranial nerves
How many pairs of spinal nerves named for the site of which they exit the spinal cord
31
Some nerve fibers fromm several spinal nerves “braid” together into a single peripheral nerve called a
Plexus
The three main plexuses of spinal cord are
Cervical plexus
Brachial plexus
Lumbosacral plexus
Cervical plexus: phrenic nerves supply the
Diaphragm
What is the largest branch of the Lumbosacral plexus that supplies the thigh, lower leg and feet
Sciatic nerve
Region of the skin supplied by a single spinal nerve is termed
Dermatome
Sympathetic nervous system deals with
Fight or flight
Parasympathetic nervous system deals with
Rest and digest
Maintains homeostasis
What are the 4 E’s of sympathetic nervous system
Emergency, embarrassment, excitement, exercise
Parasympathetic: SLUDD stands for
Salivation
Lacrimation
Urination
Digestion
Deification
What are the 2 main neurotransmitters of the autonomic nervous system
Cholinergic fibers (release acetylcholine)
Adrenergic fibers (release norepinephrine)
What is a neuroblastoma
Highly malignant tumour of sympathetic nervous system
Primarily affecting young children
Mononeuropathy affects a single nerve. What are some diseases
Carpal tunnel syndrome
Sciatica
Polyneuropathy affects more than one nerve. An example is Guillain barre syndrome caused by
Autoimmune disorders (celiac, lupus)
Tumours
Toxins (alcohol)
Infections (hiv, hep, Lyme disease)
Poliomyelitis is a viral disease that is highly contagious what does it affect
Motor neurons of spinal cord and brain- paralysis of limbs and possibly respiratory muscles
Amyotrophic lateral sclerosis (Lou Gehrig disease or ALS)
hint think Steven hawking
Motor neurons are destroyed
Progressive degenerative; muscle atrophy and loss of motor control; unable to swallow talk or breath
What are the 4 regions of the brain
Cerebrum
Diencephalon
Cerebellum
Brainstem
What is the largest part of the brain and is involved in speech, reasoning, memory and personality
Cerebrum
Diencephalon includes what (2)
Hypothalamus and thalamus
Cerebellum is the 2nd largest part of the brain; connects the ____, ___, and _____ by means of the pons
Cerebrum
Brainstem
Spinal cord
What are the 3 parts of the Brainstem
Midbrain
Pons
Medulla (medulla oblongata)
All 3 parts of the Brainstem are
Two way conduction paths
Meninges: 3 layers of connective tissue surround and protect the brain and spinal cord
Dura mater
Arachnoid
Pia mater
Dura mater forms
Dural sinuses inside the skull
Cerebrospinal fluid is clear liquid that circulates in and around the brain and spinal cord. Function?
Supports and protects nervous tissue, cushions shocks
Carrie’s nutrients to the cells and transports waste products form the cells
Network of cells that produce CSF in each ventricle of the brain
Choroid plexus
4 lobes of the cerebrum
Frontal
Parietal
Occipital
Temporal
Cerebral cortex is composed of ____ matter with many folds to increase ____
Grey; surface area
Right side of the cerebrum deals with
Visual patterns
Spatial awareness
Left side of cerebrum deals with
Verbal skills
What is the corpus callosum
Band of white matter
Bridge between right and left hemispheres permitting impulses to cross from one side to the other
The cerebrum: the ____ lies between the frontal and parietal lobes of each hemisphere
Central sulcus
The cerebrum: the ____ separates the temporal lobe from the frontal and parietal lobes in each hemisphere
Lateral sulcus
Frontal lobe of cerebral cortex contains
Motor area- directs movement
2 areas important in speech
Parietal lobe of the cerebral cortex contains the
Sensory area- impulses from skin (pain and temp) are interpreted.
Memory estimates of size distance and shape
Temporal lobe of the cerebral cortex contains the
Auditory area
Memory
Occipital lobe of cerebral cortex contains the
Visual area
What is a neuron network of gray matter, located deep within each cerebral hemisphere
Basal nuclei
Basal nuclei controls
Complex patterns of body movement
Secretes dopamine
What system is located between the cerebrum and the diencephalon? What does this system help control
Limbic system
Helps control emotion and behaviour
The hippocampus functions in learning and the formation of
Long term memory
The reticular formation does what 2 things
Governs awareness
Screens out unnecessary sensory input
Diencephalon includes what 2 things
Thalamus
Hypothalamus
The thalamus sorts out
Sensory impulses and directed them to specific areas of the cerebral cortex
What 2 functions does the hypothalamus serve
Maintains homeostasis
Controls sympathetic and parasympathetic division of the ANS and pituitary gland
The midbrain forms the forward part of the brain stem; it acts as a
Relay center for certain eye and ear reflexes
The pons lie between the midbrain and the medulla in front of the cerebrum; it is responsible for
Connecting cerebellum and rest of nervous system
Some reflex actions
What are the three vital centres located in the medulla oblongata
Respiratory center
Cardiac center
Vasomotor center
The cerebellum does NOT
Initiate movement
The cerebellum is responsible for what 4 functions
Maintenance of balance
Maintenance of muscle tone
Move smoothly
Sustain normal posture
What is meningitis?
What is the cause of meningitis?
What are the effects of meningitis?
Inflammation of the brain and spinal cord coverings (meninges)
Caused by meningococcus bacteria
Effects: headaches, nausea, vomiting, stiff neck
What is encephalitis?
What are the symptoms?
What are some causes?
Inflammation of the brain
Fever, vomiting, coma
Causes: rabies, HIV, west Nile, polio
What is hydrocephalus
Abnormal accumulation of CSF in the brain
Can destroy brain tissue
More common in infants
What is a brain disorder resulting from unexplained degeneration of the cerebral cortex and hippocampus of the limbic system
Alzheimer’s disease
What is Alzheimer’s characterized by
Dementia; causes severe intellectual impairment with mood changes and confusion
What are some degenerative disease of the brain
Dementia
Huntington disease
HIV
What is a progressive neurological condition characterized by tremors, rigidity of limbs and joints, slow move to and impaired balance
Parkinson’s disease
What is affected in Parkinson’s disease
The part of the brain that produces the neurotransmitter dopamine
Affects basal network- basal nuclei (basal ganglia)
What is epilepsy
Chronic disorder resulting in seizures from abnormal electrical activity in the brain
Dilantin is a drug used to treat epilepsy; what is its effect on oral cavity
Gingival overgrowth
Epilepsy can be triggered by
Trauma
Fever
Infection
What is by far the most common brain disorder
Stroke (cerebrovascular accident)
What are the causes and risk factors of strokes
Causes: blood clot, cerebral hemorrhage or rupture of a blood vessel
Risk factors: diabetes, smoking, high BP, arterial wall damage, excess alcohol consumption
Hematoma
Localized collection of blood outside the blood vessels within the tissues
Hematoma: epidural
Bleeding between the dura mater and the skull
Hematoma: subdural
Blood accumulates in the subdural space
Hematoma: intracerebral
Bleeding into the brain tissue itself
What is cerebral palsy
What does it result in
Disorder caused by damage to the motor control areas before or during birth
Results in paralysis (of one or more limbs)
How many pairs of cranial nerves
12
