A 61 year-old male is suffering a stroke. Now he can't speak, use his right hand and arm, or walk without assistance.
History of alcohol abuse
A stroke is a sudden interruption of the blood supply to the brain.There are 3 ways this may happen:
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What is a stroke ?
The anatomy of the Brain
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The functions of the parts of the brain
Effects of alcohol on the brain
HIs Age, and overall health have depicted his symptoms
Senior Citizen
Excessive amounts of alcohol can trigger atrial fibrillation
Why do symptoms and outcomes differ so much in different patients?
Each raised area of the brain is gyrus, and each depression is a fissure or sulcus.
The cerebrum is the largest part of the brain made up of the right and left hemisphere, and sub-divided into frontal, parietal, occipital, and temporal.
The bulging anterior structure inferior to the temporal lobe is the pons.
The medulla oblongata extends downward from the pons to the spinal cord.
The cerebellum is the posterior inferior part of the brain
Immediately inferior and medial to the cerebrum is a broad curved mass of white matter called corpus callosum.
The midbrain is between and somewhat superior to the pons and the cerebellum.
The two lateral ventricles are in the cerebral hemispheres and are not readily seen
The third ventricle is the narrow space inferior to the corpus callosum and anterior to the mid brain.
The fourth ventricle is a triangular shaped space between the pons and cerebellum
The cerebral aqueduct connects the third and fourth ventricles.
Brain tissue consists of white and gray matter.
Gray matter consists of short, nonmyelinated neurons and neuron cell bodies.
White matter consists mostly of myelinated axons with some nonmyelinated axons, primarily in fiber tracts.
The thalamus consists of bilateral egg-shaped nuclei
The hypothalamus caps the brain stem and forms the inferolateral walls of the third ventricle
The pons and medulla oblongata makeup the brainstem
What directly causes a stroke?
Why does this patient have the specific symptoms he has?
How could alcohol abuse affect his risk of a stroke?
atrial fibrillation is a type of irregular heartbeat that can cause blood clots to form in the heart
If these clots move up into the brain, it can lead to a stroke
Embolic stroke: is caused when a clot breaks off from the artery wall, which can travel further down the bloodstream to block smaller arterys
Hemorrhagic stroke: (least common) is caused by the rupture or leaking of an artery either within or around the brain
Ischemic Stroke: (most common) is caused by a blockage of an artery from a thrombus or clogged blood vessel due to atherosclerosis
thrombus- blood clot
atherosclerosis- hardening of the arteries
occurs when blood circulation to a brain are is blocked and brain tissue dies of ischemia
the initial vascular blockage during a stroke is not usually disastrous. Rather it's the neuron-killing events outside the initial ischemic zone that wreak the most havoc
Temporary episodes of reversible cerebral ischemia is called Transient Ischemic Attacks (TIA)
ischemia: a reduction of blood supply that impairs the delivery of oxygen and nutrients
also called a cerebrovascular accident (CVA)
TIA's last from 5-50min and are characterized by temporary numbness, paralysis, or impaired speech
affects are not permanent
Difficulty walking, blurred vision, slurred speech, slowed reaction times, impaired memory are detectable after only a few drinks and quickly resolve when drinking stops. On the other hand, a person who drinks heavily over a long period of time may have brain deficits that persist well after he or she achieves sobriety.
A number of factors influence how and to what extent alcohol affects the brain
how much and how often a person drinks
the age at which he or she first began drinking, and how long he or she has been drinking
his or her general health status
the person's age, level of education, gender, genetic background, and family astray of alcoholism
wether he or she is at risk as a result of prenatal alcohol exposure
TIA's work as red flags for more serious CVA's
Drinking during pregnancy can lead to physical, learning, and behavioral effects in the developing brain, the most serious of which is a collection of symptoms known as fetal alcohol syndrome (FAS).
Children with FAS may have distinct facial features such as, skin folds at the corner of the eye, low nasal bridge, short nose, indistinct philtrum, small head circumference, or thin upper lip.
Their brains may have less volume (i.e., microencephaly).
They may have fewer numbers of brain cells (i.e., neurons) or fewer neurons that are able to function correctly,
FAS infants also are markedly smaller than average.
This leads to long–term problems in learning and behavior.
The brain and spinal cord begin as an embryonic structure called the neural tube
As soon as the neural tube forms, its anterior (rostral) end begins to expand and constrictions appear that mark off the three primary brain vesicles.
The primary vesicles give rise to the secondary brain vesicles which then develop rapidly to produce the major structures of the adult brain.
Prosencephalon or forebrain
Mesencephalon or midbrain
Rhombencephalon or hindbrain
The midbrain remains undivided.
The hindbrain constricts, forming the mesencephalon (after brain)and myelencephalon (spinal brain)
The forebrain divides into the telencephalon (endbrain) and diencephalon (Interbrain)
The diencephalon specializes to form the hypothalamus, thalamus, epithalamus, and retina
The telencephalon sprouts two lateral swellings that become the two cerebral hemispheres, referred collectively as the cerebrum
The mesesnxeohalon, ,metencephalon, and myelencephalon transform into the midbrain, pons, cerebellum, and the medulla oblongata
Alll these midbrain and hindbrain structures, except the cerebellum, form the brain stem.
The lateral ventricles reflect the pattern of cerebral growth
Each lateral ventricle communicates with the third ventricle in the diencephalon via a channel called an inter ventricular foramen
The third ventricle is continuous with the fourth ventricle via the canal-like cerebral aqueduct
The fourth ventricle is continuous with the central canal of the spinal cord inferiorly
The cerebral cortex enables us to be aware of ourselves and our sensations, to communicate, remember, understand, and initiate voluntary movements
Areas concerned with conscious awareness of sensation is raw sensory areas of the cortex
The multimodal association cortex receives input from multiple senses and sends outputs to multiple areas
The motor areas of the cortex control voluntary movements and lie in the posterior part of the frontal lobes
The primary (somatic) motor cortex allows us to consciously control the precise or skilled voluntary movements of our skeletal muscles
The premotor cortex helps plan movements by selecting and sequencing basic motor movements into more complex task
The Broca's area has long been considered a special motor speech area that directs the muscles involved in speech production
The frontal eye field controls voluntary movement of the eyes
The primary somatosensory cortex has neurons that receive information from the general sensory receptors and from proprioceptors
The neurons then identify the body region being simulated, an ability called spatial discrimination.
The somatosensory association cortex integrates sensory inputs(temperature, pressure, and so forth) relayed to it to produce an understanding of the object being felt
The anterior association area (prefrontal cortex) is involved with intellect, complex learning abilities, recall, and personality
The posterior association area plays a role in recognizing patterns and faces, localizing us and our surroundings in space, and binding different sensory inputs into a understandable whole
The limbic association area provides the emotional impact that makes a scene important to us
The internal cerebral white matter is responsible for communication between cerebral areas and between the cerebral cortex and lower CNS center
Association fibers connect different part of the same hemisphere
Commissural fibers connect corresponding gray areas of the two hemispheres to function as a coordinated whole
Projection Fibers tie the cortex to the rest of the nervous system and to the body's receptors and effectors.
Basal Nuclei or Basal ganglia are primarily involved in the control of movement
The thalamus is the relay station for information coming into the cerebral cortex
Within it are a large number of nuclei, each having a functional specialty, and each projects fibers to and receive fibers from a specify region of the cerebral cortex
The hypoythalamus regulates body temp, food intake, water balance, thirst, and biological rhythms and drives
The limbic system mediates emotional responses and is involved in memory processing
The midbrain contains visual and auditory reflex centers, subcortical motor centers, and nuclei for cranial nerves III an IV
The pons relays info from the cerebrum to the cerebellum and cooperates withe the medullary respiratory centers to control respiratory rate and depth
Contains nuclei of cranial nerves V-VII and projection fibers
Medulla Oblongata relays ascending sensory pathway impulse from skin and proprioceptors through nuclei cuneatus and gracilis
contains nuclei of cranial nerves VII-X and X II
Cerebellum processes info from cerebral motor cortex, proprioceptors, and visual and equilibrium pathways
Lack of speech and inability to walk may be related to alcohol
Because each person is different and symptoms and outcomes are based on the patients overall health