1. Nervous Part C
H. Biology II
Adapted

2. Cerebral Cortex Thin (2–4 mm) superficial layer of gray matter
40% of the mass of the brain
Site of conscious mind: awareness, sensory perception, voluntary motor initiation, communication, memory storage, understanding
Each hemisphere connects to contralateral side of the body
There is lateralization of cortical function in the hemispheres

3. Cerebral Hemispheres Surface markings Central sulcus
Separates the precentral gyrus of the frontal lobe and the postcentral gyrus of the parietal lobe
Longitudinal fissure
Separates the two hemispheres
Transverse cerebral fissure
Separates the cerebrum and the cerebellum

4. Parieto-occipital sulcus (on medial surface of hemisphere)
Precentral
gyrus
Central
sulcus
Postcentral
gyrus
Frontal
lobe
Parietal lobe
Parieto-occipital sulcus
(on medial surface
of hemisphere)
Lateral sulcus
Occipital lobe
Temporal lobe
Transverse cerebral fissure
Cerebellum
Pons
Medulla oblongata
Fissure
Spinal cord
(a deep
sulcus)
Gyrus
Cortex (gray matter)
Sulcus
White matter
(a)
Figure 12.6a

5. Anterior Longitudinal Frontal lobe fissure Cerebral veins and arteries
covered by
arachnoid
mater
Parietal
lobe
Left cerebral
hemisphere
Right cerebral
hemisphere
Occipital
lobe
(c)
Posterior
Figure 12.6c

6. Left cerebral hemisphere Transverse cerebral fissure Brain stem
Cerebellum
(d)
Figure 12.6d

7. Cerebral hemisphere Diencephalon Cerebellum Brain stem • Midbrain
• Pons
• Medulla oblongata
(d) Birth
Figure 12.3d

8. Functional Areas of the Cerebral Cortex
The three types of functional areas are:
Motor areas—control voluntary movement
Sensory areas—conscious awareness of sensation
Association areas—integrate diverse information
Conscious behavior involves the entire cortex

9. Sensory areas and related association areas Primary motor cortex
Motor areas
Central sulcus
Sensory areas and related
association areas
Primary motor cortex
Primary somatosensory
cortex
Premotor cortex
Somatic
sensation
Frontal eye field
Somatosensory
association cortex
Broca’s area
(outlined by dashes)
Gustatory cortex
(in insula)
Taste
Prefrontal cortex
Working memory
for spatial tasks
Wernicke’s area
(outlined by dashes)
Executive area for
task management
Working memory for
object-recall tasks
Primary visual
cortex
Visual
association
area
Vision
Solving complex,
multitask problems
Auditory
association area
Hearing
Primary
auditory cortex
(a) Lateral view, left cerebral hemisphere
Primary motor cortex
Motor association cortex
Primary sensory cortex
Sensory association cortex
Multimodal association cortex
Figure 12.8a

10. Posterior
Motor
Motor map in
precentral gyrus
Anterior
Toes
Jaw
Tongue
Primary motor
cortex
(precentral gyrus)
Swallowing
Figure 12.9

11. Posterior
Sensory
Anterior
Sensory map in
postcentral gyrus
Genitals
Primary somato-
sensory cortex
(postcentral gyrus)
Intra-
abdominal
Figure 12.9

12. Sensory areas and related association areas Primary motor cortex
Motor areas
Central sulcus
Sensory areas and related
association areas
Primary motor cortex
Primary somatosensory
cortex
Premotor cortex
Somatic
sensation
Frontal eye field
Somatosensory
association cortex
Broca’s area
(outlined by dashes)
Gustatory cortex
(in insula)
Taste
Prefrontal cortex
Working memory
for spatial tasks
Wernicke’s area
(outlined by dashes)
Executive area for
task management
Working memory for
object-recall tasks
Primary visual
cortex
Visual
association
area
Vision
Solving complex,
multitask problems
Auditory
association area
Hearing
Primary
auditory cortex
(a) Lateral view, left cerebral hemisphere
Primary motor cortex
Motor association cortex
Primary sensory cortex
Sensory association cortex
Multimodal association cortex
Figure 12.8a

13. Primary somatosensory cortex
Cingulate
gyrus
Primary
motor cortex
Premotor cortex
Central sulcus
Corpus
callosum
Primary somatosensory
cortex
Frontal eye field
Parietal lobe
Somatosensory
association cortex
Prefrontal
cortex
Parieto-occipital
sulcus
Occipital
lobe
Processes emotions
related to personal
and social interactions
Visual
association
area
Orbitofrontal
cortex
Olfactory bulb
Olfactory tract
Primary
visual cortex
Fornix
Temporal lobe
Uncus
Calcarine sulcus
Primary
olfactory cortex
Parahippocampal
gyrus
(b) Parasagittal view, right hemisphere
Primary motor cortex
Motor association cortex
Primary sensory cortex
Sensory association cortex
Multimodal association cortex
Figure 12.8b

14. Brain Add in PPT
Do some clinical connections/disorders with brain components

15. Broca’s Area Anterior to the inferior region of the premotor area
Present in one hemisphere (usually the left)
A motor speech area that directs muscles of the tongue
Is active as one prepares to speak

16. Anterior Association Area (Prefrontal Cortex)
Most complicated cortical region
Involved with intellect, cognition, recall, and personality
Contains working memory needed for judgment, reasoning, persistence, and conscience
Development depends on feedback from social environment

17. Limbic Association Area
Part of the limbic system
Provides emotional impact that helps establish memories

18. Ventricles of the Brain
Connected to one another and to the central canal of the spinal cord
Lined by ependymal cells
Contain cerebrospinal fluid
Two C-shaped lateral ventricles in the cerebral hemispheres
Third ventricle in the diencephalon
Fourth ventricle in the hindbrain, dorsal to the pons, develops from the lumen of the neural tube

19. Lateral ventricle Septum pellucidum Anterior horn Posterior horn
Inferior
horn
Interventricular
foramen
Lateral
aperture
Median
aperture
Third ventricle
Inferior horn
Lateral
aperture
Cerebral aqueduct
Fourth ventricle
Central canal
(a) Anterior view
(b) Left lateral view
Figure 12.5

20. Regions and Organization of the CNS
Spinal cord
Central cavity surrounded by a gray matter core
External white matter composed of myelinated fiber tracts

21. Central cavity Cortex of gray matter Migratory pattern of neurons
Inner gray
matter
Cerebrum
Outer white
matter
Cerebellum
Gray matter
Region of cerebellum
Central cavity
Inner gray matter
Outer white matter
Gray matter
Brain stem
Central cavity
Outer white matter
Inner gray matter
Spinal cord
Figure 12.4

22. Reflex Arc

23. Spinal Cord Trauma Functional losses
Parasthesias
Sensory loss
Paralysis
Loss of motor function
Flaccid paralysis—severe damage to the ventral root or ventral horn cells
Impulses do not reach muscles; there is no voluntary or involuntary control of muscles
Muscles atrophy

24. Spinal Cord Trauma
Spastic paralysis—damage to upper motor neurons of the primary motor cortex
Spinal neurons remain intact; muscles are stimulated by reflex activity
No voluntary control of muscles

25. Spinal Cord Trauma Transection
Cross sectioning of the spinal cord at any level
Results in total motor and sensory loss in regions inferior to the cut
Paraplegia—transection between T1 and L1
Quadriplegia—transection in the cervical region

26. Poliomyelitis
Destruction of the ventral horn motor neurons by the poliovirus
Muscles atrophy
Death may occur due to paralysis of respiratory muscles or cardiac arrest
Survivors often develop postpolio syndrome many years later, as neurons are lost

27. Amyotrophic Lateral Sclerosis (ALS)
Also called Lou Gehrig’s disease
Involves progressive destruction of ventral horn motor neurons and fibers of the pyramidal tract
Symptoms—loss of the ability to speak, swallow, and breathe
Death typically occurs within five years
Linked to glutamate excitotoxicity, attack by the immune system, or both

28. Multiple Sclerosis (MS)
An autoimmune disease that mainly affects young adults
Symptoms: visual disturbances, weakness, loss of muscular control, speech disturbances, and urinary incontinence
Myelin sheaths in the CNS become nonfunctional scleroses
Shunting and short-circuiting of nerve impulses occurs
Impulse conduction slows and eventually ceases

29. Multiple Sclerosis: Treatment
Some immune system–modifying drugs, including interferons and Copazone:
Hold symptoms at bay
Reduce complications
Reduce disability

30. Developmental Aspects of the CNS
CNS is established during the first month of development
Gender-specific areas appear in both brain and spinal cord, depending on presence or absence of fetal testosterone
Maternal exposure to radiation, drugs (e.g., alcohol and opiates), or infection can harm the developing CNS
Smoking decreases oxygen in the blood, which can lead to neuron death and fetal brain damage

31. Developmental Aspects of the CNS
Age brings some cognitive declines, but these are not significant in healthy individuals until they reach their 80s
Shrinkage of brain accelerates in old age
Excessive use of alcohol causes signs of senility unrelated to the aging process