Chapter 15 Exam 2 Flashcards
Intracranial Regulation
This concept represents mechanisms that facilitate or impair neurologic function. Because brain function requires perfusion of oxygenated blood and because the respiratory & cardiovascular systems are impacted by neurologic control, strong bidirectional interrelationships among these concepts exist
Both sensory and tactile perception and motion are extensions of neurologic function that impact what?
Other interrelated concepts such as nutrition, development (functional ability), elimination and pain
Explain the example of a stroke using the interrelationships of intracranial regulation.
- A stroke results from lack of oxygenated blood to the brain
1) Following a stroke an individual may experience problems w/sensory and tactile perception and motion
2) This leads to impacting nutrition, elimination, pain perception and functional ability
Structural divisions of the nervous system
1) Central nervous system (CNS): brain and spinal cord
2) Peripheral nervous system (PNS) which includes all nerve fibers outside brain and spinal cord
3) Autonomic nervous system (ANS)
Foramen magnum
Large oval opening at the base of the occipital bone through which the spinal cord extends from the medulla oblongata
Meninges
Are between the skull and the brain.
There are 3 layers
1) Dura mater: outer fibrous layer
2) Arachnoid: middle meningeal layer, two layer fibrous, elastic membrane that covers the folds and fissures of the brain
3) Pia mater: the inner meningeal layer contains small vessels that supply blood to the brain
-between the arachnoid and the pia mater is the subarachnoid space where the cerebrospinal fluid (CSF) circulates
Falx cerebri
A fold of dura mater that separates the two cerebral hemispheres
Tentorium cerebelli
A fold of dura mater the supports the temporal and occipital lobes and separates the cerebral hemispheres from the cerebellum
Supratentorial and infratentorial
Supratentorial: structures above the tentorium cerebelli
Infratentorial: Structures below the tentorium cerebelli
CFS is colorless, odorless fluid made in the choroid plexes of ventricles that contains?
Glucose, electrolytes, oxygen, water, carbon dioxide, protein, and leukolytes. It circulates around the brain and spinal cord to provide a cushion, maintain normal intracranial pressure, provide nutrition, and remove metabolic wastes
The cerebral ventricular system consists of four interconnecting chambers or ventricles that produce and circulate CSF
1) One lateral ventricle in each hemisphere, with a third ventricle adjacent to the thalamus
2) A third ventricle adjacent to the thalamus
3) A fourth ventricle adjacent to the brainstem
- The CSF circulates from the lateral ventricles through the interventricular foramen to the third ventricle and through the aqueduct of Sylvius to the fourth ventricle & into the cisterna magna from there the CSF flows w/in the subarachnoid space up around the brain & down around the spinal cord.
- CSF absorbed through arachnoid villi that extend into the subarachnoid space and is returned to the venous system
The brain consists of what?
1) Cerebrum
2) Diencephalon
3) Cerebellum
4) Brainstem
- It is made up of gray matter (unmyelinated cell bodies) and white matter (myelinated nerve fibers)
What supplies most of the blood to the brain?
The carotid arteries & they branch off into the posterior cerebral, middle cerebral, and anterior cerebral arteries.
- Remaining blood flows through two vertebral arteries & into the posterior and anterior communicating arteries that supply blood through the circle of willis.
- Blood leaves the brain through venous sinuses that empty into the jugular veins
Cerebrum is the largest part of the brain and is composed of two hemispheres. Each hemisphere is divided into four lobes, describe each lobe
1) Frontal lobes: control intellectual function, awareness of self, personality, and autonomic responses related to emotion
2) Left frontal lobe contains broca’s area which is involved in formulation of words
- the frontal lobes contain the primary motor cortex & are also responsible for functions related to voluntary motor activity
Nerves from the motor cortex cross over in the medulla oblongata so that nerves on the right side of the frontal lobe control movement on the?
Left side of the body and nerves on the right side of the frontal lobe control movement on the right side of the body.
The parietal lobes contain
The primary somesthetic (sensory) cortex.
- one of its major functions is to receive sensory input such as position sense, touch, shape, and texture of objects
The sensory nerves from the body cross over the medulla, so that nerve impulses from the right side of the body are received in the?
Left side of the parietal lobe and impulses from the left side are received in the right side of the parietal lobe
The temporal lobe contains?
The primary auditory cortex. Wernick’s area located in the left temporal lobe, is responsible for comprehension of spoken and written language. The temporal lobe also interprets auditory, visual, and somatic sensory inputs that are stored in thought and memory
The occipital lobes contain?
The primary visual cortex and are responsible for receiving & interpreting visual information
What makes up the Diencephalon?
1) Thalamus: Relay and integration station from the spinal cord to the cerebral cortex & other parts of the brain.
2) Hypothalamus: Several functions in maintaining homeostasis & include regulation of body temp., hunger & thirst; formation of ANS responses; & storage & secretion of hormones from pituitary gland
3) Epithalamus: Contains pineal gland which causes sleepiness & helps regulate some endocrine function
4) Subthalamus: pare of basal ganglia
Basal Ganglia is between the cerebral cortex and midbrain and adjacent to the diencephalon, the structures that form the basal ganglia include?
The putamen, caudate nucleus, globus pallidus, thalamus, red nucleus, and substantia nigra.
-Function of the basal ganglia is to create smooth, coordinated voluntary movement by balancing the production of two neurotransmitters: acetylcholine and dopamine
The brainstem is made up of?
The midbrain, pons & medulla oblongata.
-10 of the 12 cranial nerves originate from the brainstem
Midbrain function
Function is to relay stimuli concerning muscle movement to other brain structures. Contains part of the motor tract pathways that control reflex motor movements in response to visual & auditory stimuli. Oculomotor nerve (CN III) & trochlear nerve (CN IV) originate in the midbrain
Pons function
Relay impulses to brain centers & lower spinal nerves. The cranial nerves that originate in the pons are trigeminal (CN V), abducens (CN VI), facial (CN VII), and acoustic (CN VIII)
Medulla Oblongata function
Contains reflex centers for controlling involuntary functions such as breathing, sneezing, swallowing, coughing, vomiting, and vasoconstriction.
- Motor & sensory tracts from the frontal & parietal lobes cross from one side to the other in the medulla, so lesions on the right side of the brain create abnormal movement & sensation on the left side & vise versa.
- Cranial nerves that originate in the medulla are glossopharyngeal (CN IX), vagus (CN X), spinal accessory (CN XI), and hypoglossal (CN XII)
The cerebellum is separated from the cerebral cortex by the tentorium cerebelli. Functions of the cerebellum include?
Coordinating movement, equilibrium, muscle tone, and proprioception. Each of the cerebellar hemispheres controls movement for the same (ipsilateral) side of the body
The spinal cord is a continuation of the medulla oblongata that begins at the foramen magnum and ends at the first and second lumbar (L1, L2) vertebrae. At L1 & L2 the spinal cord branches into lumbar and sacral nerve roots termed the?
Cauda equina
The spinal cord consists of ____ segments, each giving rise to a pair of spinal nerves. Nerve fibers,
31
White matter of the spinal cord
Myelinated nerves that contain ascending and descending tracts of nerve fibers.
- The descending, or motor, tracts (e.g. anterior and lateral corticospinal or pyramidal tracts) carry impulses from the frontal lobe to muscles for voluntary movement. They also play a role in muscle tone and posture.
- The ascending, or sensory, tracts carry sensory information from the body through the thalamus to the parietal lobe. The fasciculus gracilis track travels in the posterior (dorsal) column carrying sensations of touch, deep pressure, vibration, position of joints, stereognosis, and two-point discrimination.
- the lateral spinothalamic tract carries fibers for sensation of light touch, pressure, temperature, and pain
The gray matter of the spinal cord
Contains the nerve cell bodies, is arranged in a butterfly shape w/anterior and posterior horns
Peripheral nervous system
Cranial nerves, spinal nerves, reflex arch
Peripheral nervous system: Cranial nerves
Of the 12 pairs of cranial nerves, some have only motor fibers (five pairs) or only sensory fibers (three pairs); whereas others have both (four pairs). Each cranial nerve controls movement or sensation for the same (ipsilateral) side of the body
Peripheral nervous system: Spinal nerves
The 31 pairs of spinal nerves emerge from different segments of the spinal cord: 8 pairs of cervical, 12 pairs of thoracic, 5 pairs of lumbar, 5 pairs of sacral, and 1 pair of coccygeal
- The first seven cervical nerves exit above their corresponding vertebrae. There are 8 cervical nerves but 7 cervical vertebra.
- Remaining spinal nerves exit below the corresponding vertebrae
Each pair of spinal nerves is formed by the union of an efferent, or motor (ventral), root and an afferent, or sensory (dorsal), root. The motor fibers carry impulses from? Sensory nerve fibers?
Motor: carry impulses from the sensory receptors of the body through the spinal cord to muscles and glands
Sensory fibers carry impulses from the sensory receptors of the body through the spinal cord to the brain (parietal lobe).
Each pair of spinal nerves and its corresponding part of the spinal cord make up?
a spinal segment and innervate specific body segments
The dorsal root of each spinal nerves supplies the?
Sensory innervation to a segment of the skin known as a dermatome (e.g. is patient complains of pain w/numbness and tingling across the right knee, the nurse knows that the fourth lumbar spinal segment is involved, perhaps compressed
Reflex arc
Are tested by observing muscle movement in response to sensory stimuli.
- Deep tendon reflexes are responses to stimulation of a tendon that stretches the neuromuscular spindles of a muscle group. Striking a deep tendon stimulates a sensory neuron that travels to the spinal cord where it stimulates an interneuron that stimulates a motor neuron to create movement.
- Superficial reflexes are tested in same manner. Each reflex corresponds to a specific spinal segment
Autonomic Nervous System (ANS)
Regulates the internal environment of the body in conjunction w/endocrine system. It has two components: sympathetic nervous system (SNS) & the parasympathetic nervous system (PNS)
Autonomic Nervous System (ANS): Sympathetic nervous system
Arises from the thoracolumbar segments of the spinal cord and is activated during stress (fight or flight responses).
Actions: Increases BP, HR, vasoconstricting peripheral blood vessels, inhibiting gastrointestinal peristalsis, dilating bronchi
Autonomic Nervous System (ANS): Parasympathetic nervous system
Arises from craniosacral segments of the spinal cord & controls vegetative functions (breed and feed, rest and digest).
Actions: functions associated w/conserving energy such as decreasing HR and force of myocardial contractions, decreasing BP & respirations, & stimulating gastrointestinal peristalsis
Cranial nerves
I. Olfactory II. Optic III. Oculomotor IV. Trochlear V. Trigeminal VI. Abducens VII. Facial VIII. Acoustic or vestibulocochlear IX. Glossopharyngeal X. Vagus XI. Spinal accessory XII. Hypoglossal
Cranial Nerve I
Olfactory: sensory, smell
Cranial Nerve II
Optic: sensory, sight
Cranial Nerve III
Oculomotor: Motor, raise eyelids, most extraocular movements
Parasympathetic: pupillary constriction, change lens shape
Cranial Nerve IV
Trochlear: motor, downward, inner eye movement
Cranial nerve V
Trigeminal: motor, Jaw opening and clenching chewing and mastication
sensory, sensation to cornea, iris, lacrimal glands, conjunctiva, eyelids, forehead, nose, nasal & mouth mucosa, teeth, tongue, ear, facial skin
Cranial nerve VI
Aducens: motor, lateral eye movement