1. Principal Parts of the Brain
Cerebrum
Diencephalon
thalamus & hypothalamus

2. Chapter 14 The Brain and Cranial Nerves
Largest organ in the body at almost 3 lb.
Brain functions in sensations, memory, emotions, decision making, behavior
Cerebellum
Brainstem
medulla, pons & midbrain

3. Protective Coverings of the Brain
Bone, meninges & fluid
Meninges same as around the spinal cord
dura mater
arachnoid mater
pia mater

4. Blood Supply to Brain
Arterial blood supply is branches from circle of Willis on base of brain (page 699)
Vessels on surface of brain----penetrate tissue
Uses 20% of our bodies oxygen & glucose needs
blood flow to an area increases with activity in that area
deprivation of O2 for 4 min does permanent injury
at that time, lysosome release enzymes
Blood-brain barrier (BBB)
protects cells from some toxins and pathogens
proteins & antibiotics can not pass but alcohol & anesthetics do

5. Cerebrospinal Fluid (CSF)
ml (3-5oz)
Clear liquid containing glucose, proteins, & ions
Functions
mechanical protection
floats brain & softens impact with bony walls
chemical protection
optimal ionic concentrations for action potentials
circulation
nutrients and waste products to and from bloodstream

6. Drainage of CSF from Ventricles
One median aperture & two lateral apertures allow CSF to exit from the interior of the brain

7. Reabsorption of CSF Reabsorbed through arachnoid villi
grapelike clusters of arachnoid penetrate dural venous sinus
20 ml/hour reabsorption rate = same as production rate

8. Hydrocephalus
Blockage of drainage of CSF (tumor, inflammation, developmental malformation, meningitis, hemorrhage or injury
Continued production cause an increase in pressure --- hydrocephalus
In newborn or fetus, the fontanels allow this internal pressure to cause expansion of the skull and damage to the brain tissue
Neurosurgeon implants a drain shunting the CSF to the veins of the neck or the abdomen

9. Medulla Oblongata Continuation of spinal cord
Nuclei of 5 cranial nerves
Cardiovascular center
force & rate of heart beat
diameter of blood vessels
Respiratory center
medullary rhythmicity area sets basic rhythm of breathing
Information in & out of cerebellum
Reflex centers for coughing, sneezing, swallowing etc

10. XII = Hypoglossal Nerve
Controls muscles of tongue during speech and swallowing
Injury deviates tongue to injured side when protruded
Mixed, primarily motor

11. X = Vagus Nerve Receives sensations from viscera
Controls cardiac muscle and smooth muscle of the viscera
Controls secretion of digestive fluids

12. IX = Glossopharyngeal Nerve
Stylopharyngeus m. (lifts throat during swallowing)
Secretions of parotid gland
Somatic sensations & taste on posterior 1/3 of tongue

13. Injury to the Medulla Hard blow to the back of the head may be fatal
Cranial nerve malfunctions on same side as injury; loss of sensation or paralysis of throat or tongue; irregularities in breathing and heart rhythm

14. Pons One inch long White fiber tracts ascend and descend
Pneumotaxic & apneustic areas help control breathing
Middle cerebellar peduncles carry sensory info to the cerebellum
Cranial nerves 5 thru 7

15. VII = Facial Nerve Motor portion Sensory portion facial muscles
salivary & nasal and oral mucous glands & tears
Sensory portion
taste buds on anterior 2/3’s of tongue

16. Midbrain
One inch in length
Extends from pons to diencephalon

17. Cerebellum 2 cerebellar hemispheres and vermis (central area) Function
correct voluntary muscle contraction and posture based on sensory data from body about actual movements
sense of equilibrium

18. Thalamus
1 inch long mass of gray mater in each half of brain (connected across the 3rd ventricle by intermediate mass)
Relay station for sensory information on way to cortex
Crude perception of some sensations

19. Thalamic Nuclei Nuclei have different roles
relays auditory and visual impulses, taste and somatic sensations
receives impulses from cerebellum or basal ganglia
anterior nucleus concerned with emotions, memory and acquisition of knowledge (cognition)

20. Hypothalamus Dozen or so nuclei in 4 major regions
mammillary bodies are relay station for olfactory reflexes; infundibulum suspends the pituitary gland
Major regulator of homeostasis
receives somatic and visceral input, taste, smell & hearing information; monitors osmotic pressure, temperature of blood

21. Functions of Hypothalamus
Controls and integrates activities of the ANS which regulates smooth, cardiac muscle and glands
Synthesizes regulatory hormones that control the anterior pituitary
Contains cell bodies of axons that end in posterior pituitary where they secrete hormones
Regulates rage, aggression, pain, pleasure & arousal
Feeding, thirst & satiety centers
Controls body temperature
Regulates daily patterns of sleep

22. Epithalamus Pineal gland endocrine gland the size of small pea
secretes melatonin during darkness
promotes sleepiness & sets biological clock

23. Subthalamus & CVO Circumventricular organs
sites of entry of HIV virus into brain (dementia)

24. Cerebrum (Cerebral Hemispheres)
Cerebral cortex is gray matter overlying white matter
2-4 mm thick containing billions of cells
grew so quickly formed folds (gyri) and grooves (sulci or fissures)
Longitudinal fissure separates left & right cerebral hemispheres
Corpus callosum is band of white matter connecting left and right cerebral hemispheres
Each hemisphere is subdivided into 4 lobes

25. Lobes and Fissures Longitudinal fissure (green) Frontal lobe
Central sulcus (yellow)
precentral & postcentral gyrus
Parietal lobe
Parieto-occipital sulcus
Occipital lobe
Lateral sulcus (blue)
Temporal lobe
Insula

26. Basal Ganglia
Control large automatic movements of skeletal muscles

27. Limbic System Emotional brain--intense pleasure & intense pain
Strong emotions increase efficiency of memory

28. Brain Injuries Causes of damage
displacement or distortion of tissue at impact
increased intracranial pressure
infections
free radical damage after ischemia
Concussion---temporary loss of consciousness
headache, drowsiness, confusion, lack of concentration
Contusion--bruising of brain (less than 5 min unconsciousness but blood in CSF)
Laceration--tearing of brain (fracture or bullet)
increased intracranial pressure from hematoma

29. Aphasia
Language areas are located in the left cerebral hemisphere of most people
Inability to use or comprehend words = aphasia
nonfluent aphasia = inability to properly form words
know what want to say but can not speak
damage to Broca’s speech area
fluent aphasia = faulty understanding of spoken or written words
faulty understanding of spoken or written words
word deafness = an inability to understand spoken words
word blindness = an inability to understand written words
damage to common integrative area or auditory association area

30. Hemispheric Lateralization
Functional specialization of each hemisphere more pronounced in men
Females have larger connections between 2 sides
Damage to left side produces aphasia
Damage to same area on right side produces speech with little emotional inflection

31. Electroencephalogram (EEG)
Brain waves are millions of nerve action potentials in cerebral cortex
diagnosis of brain disorders (epilepsy)
brain death (absence of activity in 2 EEGs 24 hours apart)
Alpha -- awake & resting
Beta -- mental activity
Theta -- emotional stress
Delta -- deep sleep

32. II -- Optic Nerve
Connects to retina supplying vision

33. I -- Olfactory Nerve
Extends from olfactory mucosa of nasal cavity to olfactory bulb
Sense of smell

34. Dorsal View of Neural Groove

35. Aging & the Nervous System
Years 1 to 2
rapid increase in size due to increase in size of neurons, growth of neuroglia, myelination & development of dendritic branches
Early adulthood until death
brain weight declines until only 93% by age 80
number of synaptic contacts declines
processing of information diminishes
conduction velocity decreases
voluntary motor movements slow down
reflexes slow down

36. Cerebrovascular Accident (CVA)
Third leading cause of death after heart attacks and cancer
2 types of strokes
ischemic due to decreased blood flow
hemorrhagic due to rupture of blood vessel
Risk factors
high blood pressure, high cholesterol, heart disease, diabetes, smoking, obesity, alcohol
Tissue plasminogen activator (t-PA) used within 3 hours of onset will decrease permanent disability

37. Transient Ischemic Attack (TIA)
Episode of temporary cerebral dysfunction
Cause
impaired blood flow to the brain
Symptoms
dizziness, slurred speech, numbness, paralysis on one side, double vision
reach maximum intensity almost immediately
persists for 5-10 minutes & leaves no deficits
Treatment is aspirin or anticoagulants; artery bypass grafting or carotid endarterectomy

38. Alzheimer Disease (AD)
Dementia = loss of reasoning, ability to read, write, talk, eat & walk
Afflicts 11% of population over 65
Loss of neurons that release acetylcholine
Plaques of abnormal proteins outside neurons
Tangled protein filaments within neurons
Risk factors -- head injury, heredity
Beneficial effects of estrogen, vitamin E, ibuprofen & ginko biloba