Pathophysiology Ch. 13

Functions of the Forebrain:

(consists of the diencephalon and telencephalon) -Thalamus: "switchboard" or relay station for impulses going to and coming from the cerebrum -Hypothalamus: homeostatic control -Cerebral hemispheres -Gives rise to cranial nerves I and II, for smell and sight

Neurotrophic factors

(relating to growth of nervous tissue) -proliferation -differentiation -survival of neuronal and nonneuronal cells -chemical messengers

Functions of the Midbrain:

-Cerebral peduncles carry nerve fibers from the forebrain and pons in the hindbrain -Superior colliculi control reflex eye movements -Inferior colliculi control reflex reactions to sound -Gives rise to cranial nerves III and IV, controlling eye movement

Maintenance of blood gas concentrations, water balance, and food consumption are controlled by which part of the brain?

-Hypothalamus

Functions of the Hindbrain:

-Medulla oblongata, cerebellum, and pons -Reflex centers for heart and respiration rates, coughing, swallowing, vomiting, etc. -Give rise to cranial nerves controlling hearing, facial, and mouth/throat functions -The cerebellum is the movement control center -Cranial nerves: V, VI, VII, VIII, IX, X, XI, XII (5-12)

Na+ influx in the soma results in: •K+ efflux results in:

-Na+ Influx = Depolarization of membrane -this triggers voltage-gated Na+ and K+ channels in the axon -K+ Efflux results in: Repolarization of the membrane (NIDKER)

Disorders/Diseases involving basal ganglia that result in dysregulation of movements:

-Parkinson disease -Huntington chorea -forms of cerebral palsy

Preganglionic vs. Postganglionic

-Preganglionic: neurons located in the brain stem and spinal cord -Postganglionic: neurons located in the PNS

Microglia

-act as phagocytes, eating damaged/dead cells, bacteria, and waste -act as the brains immune system -in CNS

Reabsorption of cerebrospinal fluid (CSF) into the vascular system occurs due to which structure? Arachnoid villa Pia mater Tentorium cerebelli Choroid plexus

-arachnoid villa

3 Parts of the Neuron:

-cell body: controls cell activity -dendrites: conducts/receives info to cell body -axon: carries impulses away from cell body

Myotatic/Stretch Reflex:

-controls muscle tone and helps maintain posture

Which of the meninges provides the major protection for the brain and spinal cord? Dura mater Pia mater Arachnoid membrane Tentorium cerebelli

-dura mater

Satellite Cells

-flattened capsular cells -secrete basement membrane to protect neurons -in PNS

Schwann Cells

-form myelin sheath around axons -in PNS -wrap continuously around themselves to form myelin sheath -gaps in between Schwann cells are called: Nodes of Ranvier

Oligodendrocytes

-form myelin sheath on axons (has several processes/arms) -in CNS -myelin is what gives white matter it's white color

A client arrives in the clinic after having a tongue piercing performed and is unable to control the movement of the tongue. The nurse is aware that which nerve may have been damaged from the piercing?

-hypoglossal (CN XII)

Withdrawal Reflex:

-is stimulated by a damaging (nociceptive) stimulus and quickly moves the body part away from the offending stimulus. -shifts postural support to the opposite side of the body -can produce contraction of muscles other than the extremities (irritation of the abdominal viscera may cause contraction of abdominal muscles)

Parietal lobe:

-lies behind central sulcus -localized lesions in parietal lobe can result in agnosia: (inability to recognize the meaningfulness of an object; people can describe the object but not know what it does).

Ependymal Cells

-line cavities of the brain and spinal cord -produces and circulates cerebrospinal fluid -in CNS

Neuromodulators:

-long-term changes to enhance or depress receptor action -chemical messengers

The nurse is aware that the primary function of the sympathetic nervous system is:

-maintenance of vital functions and responding when there is a critical threat to the integrity of the individual.

Astrocytes

-most abundant of neuroglial cells -provide structural and metabolic support for neurons -form blood brain barrier -repair and scar formation in brain (gliosis) -maintain potassium ion concentration -in CNS

Stereognosis:

-sensing the shape and size of an object in the absence of visualization -requires precise information from muscle, tendon, and joint receptors.

Neurotransmitters:

-signal across synapses -excitatory or inhibitory -3 major neurotransmitters: (amino acids, monoamines, peptides)(AAMP) -chemical messengers

Action potentials: the movement of electrical charge along the axon membrane; frequency conveys information 3 phases of APs:

-the movement of electrical charge along the axon membrane; frequency conveys information -resting or polarized phase -depolarization -repolarization

Which process may increase(s) the permeability of the blood-brain barrier? Select all that apply. Trauma Infection Hypovolemia Hypertension Severely jaundiced infants

-trauma -infection -severely jaundiced infants

Gliosis:

-when astrocytes fill their cytoplasm with microfibrils. Masses of these cells form scar tissue in the brain.

A released transmitter can undergo one of these three processes:

1. It can be broken down into inactive substances by enzymes 2. It can be taken back up into the presynaptic neuron in a process called reuptake 3. It can diffuse into the intercellular fluid until its concentration is too low to influence postsynaptic excitability

A practitioner is preparing to do a lumbar puncture on a client with suspected meningitis. Which area on the spine does the practitioner choose to obtain a cerebrospinal fluid (CSF) sample?

Between L3 and L4

Which area of the brain is responsible for respiration? Brain stem Midbrain Diencephalon Frontal lobe

Brain stem

31 pairs of Spinal Nerves:

Cervical- 8 pairs Thoracic- 12 pairs Lumbar- 5 pairs Sacral- 5 pairs Coccygeal- 1 pair

The cerebellum, separated from the cerebral hemispheres by the tentorium cerebelli, lies in the posterior fossa of the cranium. What is one of the functions of the cerebellum?

Coordinates smooth and accurate movements of the body

The nurse measures a blood glucose level of 40 mg/dL (2.22 mmol/L) for a client with type 1 diabetes. Why would it be important for the nurse to institute an intervention to elevate the glucose level in this client?

Glucose is not stored in the brain and is a major fuel source for brain function.

Cranial Nerves of Forebrain:

I & II (1-2)

Cranial Nerves of Midbrain:

III & IV (3-4)

Cranial Nerves in Medulla

IX, X, XI, XII (9-12)

The health care provider is performing a spinal tap on a client with suspected infection. The provider would perform the procedure at:

L3 or L4

A 60-year-old woman has been recently diagnosed with multiple sclerosis, a disease in which the oligodendrocytes of the client's central nervous system (CNS) are progressively destroyed. Which physiologic process within the neurologic system is most likely to be affected by this disease process?

Nerve conduction

Which hormone will elicit a more rapid response than the others? Norepinephrine Adrenocorticotropic hormone Insulin Prolactin

Norepinephrine

Newer systems control older systems but are easier to damage. They also have more finite control of the body.

Older systems are more hardwired, making harder to damage. Ex. How someone can be brain dead but can still breathe.

Neurotransmitters exert their actions through specific proteins that are known as: Receptors Transformers Antibodies Autoantigens

Receptors

The vertebral column provides protection of which parts of the body? Select all that apply. Spinal cord Spinal nerves Supporting structures Muscles Tendons

Spinal cord Spinal nerves Supporting structures

The nurse is performing a neurologic assessment on a client. Which assessment finding would the nurse determine is considered normal? The client is able to swing arms when walking. Hesitates for 10 seconds and then able to blink eyes on command. The client is unable to distinguish between two smells such as lemon and alcohol. The client cannot recognize a coin when placed in the hand but can recognize a cotton ball.

The client is able to swing arms when walking.

Cranial Nerves is Pons

V, VI (5-6)

College students were given various amounts of alcohol within a specified time frame and then asked to drive an obstacle course. The rationale for poor performance in driving as the amount of alcohol intake increased includes, "The blood-brain barrier:

allows alcohol, a very lipid-soluble molecule, to rapidly enter the brain."

The parasympathetic nervous system is part of which system? Central nervous system Somatic nervous system Autonomic nervous system Thoracolumbar nervous system

autonomic nervous system

Function of the occipital lobe:

color, motion, and depth perception

Which substance provides the majority of the fuel needs of the neurologic system?

glucose

Major neurotransmitters of the sympathetic nervous system:

•Adrenergic neurotransmitter (sympathetic): -dopamine -epinephrine -norepinephrine

Afferent vs. Efferent

•Afferent: sensory (incoming) •Efferent: motor (outgoing)

Primary neurotransmitter of the parasympathetic nervous system:

•Cholinergic neurotransmitter (parasympathetic): -acetylcholine

Inner layer of white matter

•Connects neighboring segments •Short fibers •Reticular activating system

Middle layer of white matter

•Fibers reach to the brain stem •Ascending tracts

Cerebrospinal Fluid

•Leaks out of capillaries inside the brain's hollow ventricles •Composition controlled by the blood-brain barrier •Passes out an opening below the cerebellum •Circulates around the brain and spinal cord in the subarachnoid space •Passes through arachnoid villi into blood in the dural sinuses and is returned to the heart

Outer layer of white matter

•Pathways for bladder control and fine motor skills •Develop by fifth year of life •Most vulnerable

Sympathetic Nervous System

•fight or flight part of ANS •Increase heart rate, blood pressure •Dilate pupils, bronchioles •Blood from the GI, skin to skeletal muscles, brain

Parasympathetic Nervous System

•rest or digest part of ANS •Decrease heart rate, blood pressure •Constrict pupils •Blood to the GI tract, increased secretions