1

Motor Areas anterior part of each hemisphere

primary motor area controls voluntary contraction of specific muscles or

groups of muscles more area for muscles of skilled, complex, or delicate

movement Broca’s speech area

left frontal lobe for 97% of population planning and production of speech from Broca’s to

premotor area to motors of larynx, pharynx, mouth

primary motor area to control breathing muscles

2

Figure 15.5b

3

Association Areas often adjacent to primary sensory areas usually receive input from both primary

sensory areas and other brain regions integrate sensory experiences to generate

meaningful patterns of recognition and awareness

damage to primary visual area of brain results in loss of vision

damage to visual association area would not recognize what they are seeing

4

Association Areas somatosensory association area

integrates and interprets sensations determines shape and texture of object without looking at

it determines orientation of one object with respect to

another as they are felt sense relationship of one body part to another storage of memories of past experiences to compare

current sensations with previous experiences visual association area

receives sensory impulses from primary visual area and thalamus

relates present and past visual experiences essential in recognizing and evaluating what is seen

5

Association Areas auditory association area

allows recognition of sound as speech, music, or noise Wernicke’s area

broad region in left temporal and parietal lobes interprets meaning of speech by recognizing spoken

words translates words into thoughts right hemisphere correspond to Broca’s and Wernicke’s

in the left contribute to verbal communication by adding

emotional content like anger, joy, or spoken words

6

Association Areas common integrative area

integrates sensory interpretations from all sensory association areas

allowing formation of thoughts based on variety of sensory inputs

transmits signals to other parts of brain to cause appropriate response

premotor area immediately anterior to primary motor area controls learned, skilled, motor activities of a complex

and sequential nature causes specific groups of muscles to contract in specific

sequence serves as memory bank for specific patterns of

movements

7

Association Areas frontal eye field area

controls voluntary scanning movements of eye reading for example

8

Hemispheric Lateralization functional asymmetry

each hemisphere also specializes in performing certain unique functions

appears at about 30 weeks in fetal development

left hemisphere receives somatic sensory signals from controls muscles on the right side of the body

right hemisphere receives and controls the left

9

Hemispheric Lateralization left hemisphere

reasoning, numerical and scientific skills spoken and written language ability to use and understand sign language

right hemisphere musical and artistic awareness spatial and pattern perception recognition of faces emotional content of language discrimination of different smells generating mental images of sight, sound, touch,

taste, and smell to compare relationships among them

10

Figure 13.11

11

Table 13.1

12

Concept 13.6 Diencephalon

13

Diencephalon extends from brain stem to cerebrum surrounds third ventricle thalamus hypothalamus pineal gland

14

Thalamus 3cm in length 80% of diencephalon paired oval masses of gray matter

organized into nuclei interspersed tracts of white matter

intermediate mass crosses third ventricle joins left and right halves of thalamus

relays and processes sensory and motor information

15

Thalamus with other parts of the brain helps regulate

autonomic activities emotions maintains consciousness pain perception learning memory cognition (thinking and knowing)

16

Figure 13.1a

17

Figure 13.1c

18

Figure 13.9a

19

Figure 13.12

20

Hypothalamus small part of diencephalon inferior to thalamus 12 or so nuclei

mammillary bodies serve as relay stations for reflexes to sense of smell

infundibulum connects pituitary gland

major regulator of homeostasis continually monitors conditions within blood

osmotic pressure, glucose levels, hormone concentrations, temperature

21

Important Functions of Hypothalamus1. Control of ANS

regulator of visceral activities including heart rate, movement of food through GI tract, contraction of urinary bladder

2. Production of hormones through bloodstream and axons to pituitary

3. Regulation of emotional and behavioral patterns

works with limbic system4. Regulation of eating and drinking

insulin passes BBB stimulating or inhibiting food intake

thirst center sensitive to osmotic pressure

22

Important Functions of Hypothalamus5. Control of body temperature

• stimulates body to promote heat loss if too hot and heat production and retention if too cold

6. Regulation of circadian rhythms and states of consciousness

• sleep and wake cycles

23

Figure 13.13ab

24

Figure 13.13c

25

Pineal Gland size of a small pea considered part of endocrine system secretes melatonin

promotes sleepiness contributes to setting of body’s biological clock

26

Concept 13.7 Brain Stem

27

Brain Stem between spinal cord and diencephalon three regions

1. midbrain

2. pons

3. medulla oblongata contain both tracts and nuclei act as relay centers for processing and controlling

involuntary of sight and sound processing eye movement regulation of autonomic functions

respiration, heart rate, blood pressure, digestion

28

Midbrain conducts nerve impulses from cerebrum to spinal

cord, medulla, and pons peduncles have axons of sensory neurons

medulla to thalamus regions

corpora quadrigemina superior colliculi

reflex centers for some visual activities inferior colliculi

reflex centers for some reactions to auditory stimuli

29

Pons anterior to cerebellum inferior to midbrain 2.5cm long tracts that connect parts of brain

e.g. left and right cerebellum voluntary movements relayed from cerebral

cortex to cerebellum help control breathing

pneumotaxic area apneustic area

30

Figure 13.1a

31

Figure 13.1c

32

Figure 13.14

33

Figure 13.15

34

Medulla Oblongata inferior part of brain stem continuation of spinal cord 3cm from pons to foramen magnum all sensory and motor tracts connecting brain

and spinal cord pyramids

white matter bulges largest motor tracts 90% of left pass to right & right to left

cardiovascular and medullary rhythmicity areas

35

Reticular Formation small clusters of neuronal cell bodies within

small bundles of myelinated axons RAS

sensory axons that project cerebral cortex helps maintain consciousness active during awakening from sleep

RAS arouses cerebral cortex

motor tracts help regulate muscle tone

36

Concept 13.8 Cerebellum

37

Functions of Cerebellum anterior and posterior lobes govern subconscious

aspects of skeletal muscle movements flocculondular lobe on inferior surface contributes to

equilibrium and balance main function

cerebellum evaluates movements smoothes movements corrects errors coordinates sequence regulates posture and balance makes possible all skilled muscular activities

38

Table 13.2 part 3

39

Concept 13.9 Spinal Cord

40

External Spinal Cord Anatomy roughly circular but flattened slightly in anterior-

posterior dimension ~2cm diameter

larger in cervical and lumbar enlargements smallest at inferior tip

adult spinal cord length from 42 to 45 cm from medulla oblongata to L2

filum terminale extension of pia mater extends inferiorly anchors spinal cord to coccyx

41

Figure 13.2

42

External Spinal Cord Anatomy

31 pair of spinal nerves exit vertebral column at intervertebral foramina each pair called spinal segment paths of communication roots

bundles of axons that connect peripheral nerves and spinal cord

posterior or dorsal root sensory neuron axons

anterior or ventral root motor neuron axons

43

Figure 13.4b

44

Internal Spinal Cord Anatomyright and left sides anterior median fissure

deep and wide groove posterior median sulcus

shallower, narrower gray matter surrounded by white matter gray matter shaped like an “H” or a butterfly gray commissure

crossbar of H connects gray matter L & R sides central canal

contiguous with 4th ventricle white commissure

anterior to gray commissure connects white matter on L & R sides

45

Internal Spinal Cord Anatomy gray matter

cell bodies, neuroglia, unmyelinated axons of sensor neurons, dendrites of interneurons, motor neurons

divided into horns anterior horn

cell bodies of somatic motor neurons and motor nuclei

posterior horn somatic and autonomic sensory nuclei

lateral gray horns absent in cervical segments cell bodies of autonomic motor neurons

regulating smooth and cardiac muscle, and glands

46

Internal Spinal Cord Anatomy white matter

bundles of myelinated and unmyelinated axons of sensory neurons, interneurons, and motor neurons

divided into columns anterior, posterior, and lateral tracts having common origin or

destination and carrying similar information over long distances

sensory tracts toward CNS

motor tracts away from CNS

47

Concept 13.10 Spinal Cord Impulses

48

Sensory Tracts

spinothalamic tracts and posterior columns lateral and anterior spinothalamic tracts

pain, warmth, coolness, itching, tickling, deep pressure, crude poorly localized sense of touch

right and left posterior columns proprioception, discriminative touch, two point

discrimination, light pressure and vibration sensations

49

Figure 13.19a

50

Figure 13.19b

51

Motor Tracts

down spinal cord in two pathways direct pathways

impulses destined to cause precise, voluntary movements of skeletal muscles

indirect pathways govern automatic movements help coordinate body movements with visual

stimuli major role in equilibrium my maintaining skeletal

muscle tone and contraction of postural muscles

52

Spinal Reflexes

spinal reflex integration occurs in spinal cord gray matter

cranial reflex integration that occurs in brain

53

End Chapter 13