• 1 handout today – “Anatomy of a Head Injury”• quiz #3 available until Monday at 11pm• quiz #3 covers chapters 14 & 15

1. If your sciatic nerve is damaged, where do you feel pain?2. If someone had a spinal cord injury that damaged area A on the diagram (posterior or dorsal columns), which spinal tract will the injury effect?3. What type of information does this tract carry?4. Where does this tract decussate?5. Identify B on the diagram. Does B carry sensory, motor or both?

A

B

Brain and Cranial Nerves

• why are we so smart?• brain directions• brain anatomy• cranial meninges• ventricles and flow of CSF• dural sinuses and venous flow• head injuries• Brainstem anatomy & function• cerebellar anatomy & function• cerebrum – anatomy & function

• lobes• sensory & motor cortex• limbic system• brain damage• cranial nerves (II, XII, V)

Does size matter???

Interneurons in SC

Interneurons in the brain

www.prokop.co.uk/

anterior posterior

cerebrum

cerebellumdiencephalon

Brain stem

dorsal

ventral

Anatomical directions and the brain

Posterior = dorsalAnterior = ventral

Corpus callosum

Thalamus Hypothalamus

Diencephalon

Brainstem

Midbrain

Pons

Medulla oblongata

Anterior

Posterior

cortex

diencephalon

Fig. 15.4(TE Art)Dura mater

Arachnoid mater

Subarachnoid space

Pia mater

Periosteal layer

Meningeal layer

Arachnoid villus

Sinus

S = skinC = connective tissueA = aponeurosisL = loose connective tissueP = periosteum

Dura mater• periosteal layer• meningeal layer• sinus

ArachnoidSubarachnoid spaceArachnoid villusPia mater

Loose connective tissue contains blood vessels and nerves

SCALP

•Subarachnoid contains cerebral spinal fluid (CSF)

Meningitis = viral, bacterial, fungal infection of blood and CSF Viral >> bacterial but bacterial is a medical emergencySymptoms: fever, headache, nausea, vomiting, light sensitivity….People living in close quarters (ie dorms) should get vaccination

Lateralventricles

Central canal

Fourthventricle

Thirdventricle

Cerebral aqueduct Lateral

ventricle

ThirdventricleCerebralaqueduct

Lateralaperture

Fourthventricle

Medianaperture

Ventricles are filled with CSF

Choroid plexus• Ependymal cells• Blood brain barrier

Lateral ventricle

Third ventricle

Fourth ventricle

Cerebral aqueduct

1

2

3

4

56

7

8

movie

“dirty” CSF is resorbed into the venous blood at the sinusesthrough the arachnoid villi

Dural sinuses drain into the:• jugular veins• basilar plexus – vertebral plexus• occlusion of sinuses• cancer metastasis

1. How do you get a head injury.

2. Where is a subdural, extradural or subarachnoid hemorrhage and how does it damage the brain?

3. What are some of the signs of a head injury?

Head injuries

Epidural hematoma

Foramen magnum

Loss of consciousnessSeizuresHeadachesDisorientationNausea and/or vomitingWeaknessSlurred speechPersonality changes

Brainstem

Brain stem = diencephalon, midbrain, pons, medulla oblongata

Medulla: controls respiration and heartbeat!

Anterior view Dorsolateral view

thalamus

Pons

colliculus

Cerebral peduncle

Medullaoblongata

Brainstem anatomy and function

Radiationsto cerebralcortex

Descendingmotorfibers

Ascendingsensory fibers

Visualinput

Auditoryinput

Reticular formation

Functions include: Somatic motor control, CV control, pain modulation, sleep & consciousness, habituation, visual attention

RF = area of grey matter in brainstem, projects to cerebrum and spinal cord

Thalamus: relay stationfor sensory input to the cortex

Hypothalamus: controls ANS & endocrine system

Diencephalon

T

Fig. 15.8(TE Art)

AnteriorAnterior lobe

Vermis

Cerebellar anatomy

Posterior lobe

Cerebellar function• coordinates joint movements• coordinates eye – motor movements• aids in planning, learning & storing motor movements• maintains muscle tone and posture• adjusts muscle performance during movement• damage to cerebellum

pons

ALPL

pons

Middle cerebellar peduncle

Fig. 15.9a(TE Art)Primarymotor area Motor assoc-iation areaPrimarysomestheticarea

Primarymotor areaMotor association area

Thalamus

Input to cerebellum Output from cerebellum

Sensory input

Vestibular

Auditory

Visual

Rubrospinal tract(fine motor control)

Fig. 15.9b(TE Art)

Spino-cerebellar

Pons and medulla

Pons

Cerebellum

Medulla

Reticularformation

proprioceptors

• quiz #3 open until Monday at 11pm• quiz #3 covers chapter 14 &15

• exam #2 Thursday May 3rd • Exam covers chapters 10, 11, 12, 13, 14 & 15

• there is a practice exam on the website

Fissure > sulcus

• Frontal lobe – cognition and “higher” mental processes, motor• Parietal lobe – receiving & interpreting general sensory & taste• Occipital lobe – visual information• Temporal lobe – hearing, smell, learning, memory, emotions• Insula – taste, hearing, visceral sensory info

Central sulcus

Visual association area

Primary visual area

Primary somatosensory areaPostcentral gyrus

Somatosensory associationarea

Motor associationarea

Primary motor areaPrecentral gyrus

Broca area: planning speech generates motor program for speech

Wernicke area: recognition of spoken & written language

Cuneate fasciculusCorticospinal tract

Primary Sensory & Motor

Areas

Fig. 15.20(TE Art)Anterior

Precentral gyrus

Centralsulcus

Vo

calizatioin

Primary Motor Area

Motor homunculus: body part inproportion to cortical area

Basal ganglia• help in planning and executing movement• degeneration of BG with Parkinson disease

Fig. 15.19(TE Art)Anterior

Postcentralgyrus

Frontallobe

Centralsulcus

Primary somatosensory area

Sensory homunculus

Prefrontal cortex

Abstract thought, judgement, foresight, responsibilitySense of socially responsible behavior, motivation

Limbic SystemHippocampus, amygdala, tracts, cingulate gyrus, thalamus, hypothalamus, forebrain

• Emotional brain• Short term memories into long term memories

thalamus

hypothalamus

hippocampus

amygdala

forebrain

taste

smell

Prefrontalcortex

hearing

vision

touch

Alzheimer’s

Brain damage

How?• head trauma• CVA or stroke• disease• cardiac arrest• alcohol poisoning • drugs….

Terry Shiavo

• in Persistent Vegetative State (PVS) for 15 years• eating disorder lead to cardiac arrest• hypokalemia (low potassium levels)• unconscious…..coma…..PVS

Coma: profound state of unconsciousness (usually eyes closed, no sleep/wake cycles)alive but unable to respond to environment (some reflexive activity)can be irreversible depending, maybe still be breathing on ownhave electrical activitycan lead to PVS

Persistent Vegetative State: severe brain damage – coma – no detectable awarenessunconscious, unresponsive, unaware (can have arousal & sleep/wake cycles)exhibit some “spontaneous” behaviors (may open & close eyes, grind teeth..)usually irreversible

Brain death: complete & irreversible cessation of brain activityno electrical activity – no CN reflexesincludes cortex & brainstemdefinition has changed (anencephaly)

Cranial nerves

Peripheral nerves that leave at the base of the brain (instead of the spinal cord)Carry sensory & motor information to head, neck and visceraThere are 12 pairs of cranial nerves I-XII (each has a name and number)Use cranial nerves to test brain function

Cranial Nerve II – Optic NerveAn example of a purely sensory cranial nerve

CN II – receives sensory information from the retina relays info to occipital lobe

Cranial Nerve XII – Hypoglossal NerveAn example of a purely motor cranial nerve

CN XII – motor information to tongue muscles responsible for swallowing, speech, chewing

Cranial Nerve V – Trigeminal NerveAn example of a mixed cranial nerve

CN V – carries sensory information from face, teeth, gums, tongue cornea, sinuses, dura mater, test using the corneal blink reflex

CN V – motor to muscles of mastication and tensor tympani

Cranial nerves

• Exam #2 Thursday• covers chapters 10-15• bring scantron and pencil