(LESSON 12) Central and Peripheral Nervous System Flashcards Preview

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Flashcards in (LESSON 12) Central and Peripheral Nervous System Deck (77):
1

Brain at week 4

Arises as the rostral part of the neural tube in embryo, immediately starts to expand. Constrictions that define three primary brain vesicles appear.

2

Three early vesicles of brain

-prosencephalon (forebrain) -mesencephalon (midbrain) -rhombencephalon (hindbrain) Caudal portion of tube becomes spinal cord

3

brain at week 5

3 primary vesicles give rise to 5 secondary brain vesicles.

  • Prosencephalon divides into
    • telencephalon (endbrain)
    • diencephalon (interbrain)
  • Mesencephalon remains
  • Rhombencephalon divides into
    • metencephalon (afterbrain)
    • myelencephalon (brain most like spinal cord)

Also develops two major bends:

  • midbrain flexure
  • cervical flexure

 

4

Telencephalon Development

Has two lateral swellings that look like mouse ears and develop into the two cerebral hemispheres of the cerebrum.

Lateral Ventricles

5

Diencephalon development

Thalamus, hypothalamus, epithalamus, third ventricle

6

Mesencephalon development

Forms midbrain, brain stem. Cerebral aqueduct

7

Metencephalon development

brainstem: pons, cerebellum, part of fourth ventricle. 

8

Myelencephalon development

medulla oblongata, part of fourth ventricle

9

Embryonic Development of the brain

(image)

10

Cerebral Cortex

Gray matter of the brain and is 2-4cm thick. Gives us consciousness and enables voluntary action. Bilateral and divided into the sensory (precentral gyrus) and motor (postcentral gyrus) areas. 

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Sensory Areas

(Cortical Areas)

cortical areas involved with conscious sensation

12

Motor areas

(Cortical Areas)

cortical areas that control motor functions

13

Multimodal Association Areas

(Cortical Areas)

Cortical areas tie sensory information together with memory

14

Lateralization of Cortical Functioning

Left hemisphere:

  • language
  • math
  • logic

Right hemisphere:

  • visual-spatial skills

  • emotion

  • art

  • music

 

15

Cerebral White Matter

  • deep to the gray matter of the cortex
  • provides communication for gray matter
  • association fibers connect different parts of the same hemisphere.
  • projection fibers ascend or descend to or from (respectively) the cerebral cortex.
  • commissures are nerve fibers that run between the two hemispheres. (largest=corpus callosum)

16

Diencephalon

  • surrounded by the cerebrum
  • composed of
    • thalamus: “gateway to the cerebral cortex”
    • hypothalamus: main visceral control center
    • epithalamus: contains the pineal gland which secretes melatonin.

17

Hypothalamus

  • autonomic control center
  • emotional response center
  • body temperature regulation
  • hunger and thirst sensations
  • control of motivational behavior
  • regulation of sleep-wake cycles
  • control of endocrine system
  • formation of memory

18

Disorders caused by injury to hypothalamus

  • severe weight loss or obesity
  • sleep disturbances
  • dehydration
  • emotional disorders

19

Cerebellum (little brain)

processes inputs from the

  • cerebral motor cortex
  • brain stem nuclei
  • sensory receptors
  • provides the timing and patterns of skeletal contraction

20

Cerebral Spinal Fluid

  • Made mostly in choroid plexus
  • About 1 liter/day is produced
  • gives buoyancy (reduces the weight of the brain by 97 percent)
  • cushions
  • nourishes (hormones, vitamins, ions)

21

Meningitis

Caused when flow and drainage of the cerebral spinal fluid in the subarachanoid space and ventricles are blocked. Meninges inflames from bacterial or viral infection. Infection can spread to enderlying nervous tissue and cause brain inflammation called encephalitis.

22

Blood brain barrier

  • maintains stable environment in the brain
  • blood-borne substances separated from the brain by endothelial capillary walls with abundant tight junctions
  • permeable to fat-soluble molecules, some anesthetics

23

Meninges

(image)

24

Alzheimer's Disease

  • Progressive degenerative disease that eventually results in dementia
  • 5-15%  over the age of 65 develop it
  • Memory loss, shortened attention span, depression, and disorientation.
  • Structural changes (areas associated with memory):
    • basal forebrain nuclei
    • hippocampus
    • association areas of cerebral cortex
  • Brain tissue contains senile plaques containing amyloid-beta peptide (between neurons), caused by an APP (amyloid precursor protein) build up, and neurofibrillar tangles (within neurons)

25

Peripheral Nervous System

Comprised of all neuron structures outside the CNS. Divided into cranial and spinal nerves. 

26

Efferent Neurons vs Afferent Neurons

Efferent=conducting messages away from CNS towards an effector organ such as a muscle or gland. 

Afferent=conducting sensory information towards the CNS.

27

Autonomic Nervous System

  • part of the efferent (motor) division of the PNS
  • motor innervation of smooth and cardiac muscle and glands

28

Sympathetic vs Parasympathetic

(divisions of ANS)

  • Sympathetic: fight or flight
  • Parasympathetic: vegetative function (digestion and resting)

29

Gustation

Taste.

  • Papilla on tongue contain taste buds

  • Saliva dissolves stimulating molecules (in foods) which bind to the microvilli cell membrane

  • Innervation of taste receptors through facial and glossopharyngeal nerves

30

Olfactory Epithelium

Epithelium on the roof of  the nasal cavity/superior nasal concha/superior nasal septum. Pseudostratified columnar epithelium that contain bipolar neurons called olfactory receptor cells. These are surrounded by columnar supporting cells. 

31

Olfactory Cilia

Each receptor cell has an apical dendrite that projects to the epithelial surface and ends in a knob from which these long cilia radiate, acting as receptive structures for smell.

32

Olfactory nerve

when the axons of the receptor cells bundle together to create filaments of the olfactory nerve. It penetrates the cribiform plate of ethmoid bone and enters the olfactory bulb of the forebrain.

33

Orbicularis oculi

thin, flat sphincter muscle that surrounds the orbit. Closes, blinks, squints.

34

Levator palpebrae superioris

Muscle that voluntarily opens the eye. Runs anteriorly from posterior roof of the orbit, enters the upper eyelid, and inserts on the tarsal plate.

35

Tarsal glands

modified sebaceous glands embedded in the tarsal plates. 25 of these glands line up side by side in the upper eyelid, with fewer in the lower eyelid. Release an oul that lubricates the surface of the eye. 

36

iris

"rainbow". The visible, colored part of the eye. Lies between cornea and lens, base attaches to ciliary body. Contains pupil.

37

Rod cells

photoreceptors that are more numerous, more sensitive to light, and permit vision in dim light. Provide neither sharp images nor color vision so things look gray and fuzzy in the dark.

38

Cone cells

Photo receptors that operate best in bright light and enable high-acuity color vision. Blue, red and green light are the three subtypes of cone cells.

39

Macula lutea

"Yellow spot". Lies precisely at the eye's posterior pole. Special area of the retina. Houses Fovea centralis. Contains mostly cones and density of cones declines with increasing distance from the macula. This is why peripheral vision isnt as sharp as central vision.

40

Fovea centralis

"Central pit". Lies directly at the center of macula lutea. A tiny pit that contains only cones and provides maximal visual acuity. This is why things are most clearly seen when we look directly at them. 

41

lens

thick, transparent, biconvex disc that changes shape to allow precise focusing of light on the retina. It is enclosed in a thick capsule and is held in place posterior to the iris by its ciliary zonule. Lacks blood vessels to maintain transparency. 

42

Visual pathway

Visual information travels to the cerebral cortex through this. 

43

Optic nerve

axons of the ganglion cells exit eye through this.

44

Optic Chiasma

the crossing, or decussation of the axons of the medial eye which lies anterior to the hypothalamus.

45

Optic tract

Uncrossed axons from the lateral side of the ipsilateral retina and crossed axons from the medial side of the contralateral retina. Tracts sweep posteriorly around hypothalamus and send most of their axons to the lateral geniculate nucleus of the thalamus.

46

Lateral geniculate nucleus of thalamus

site where the optic tract axons synapse with thalamic neurons. Post synaptic neurons project through the internal capsule to form the optic radiation of fibers in the cerebral white matter.

47

Primary visual cortex

In the occipital lobe, where the fibers from optic radiation input and conscious perception of visual images occur.

48

Optic vesicles

At week 4, paired lateral outgrowths portrude from diencephalon.

49

Optic cups/optic stalks

hollow optic vesicles indent to form double layered optic cups. The proximal parts of the outgrowths, the optic stalks, form the basis of the optic nerves.

50

Lens placode

the thickening of the ectoderm, signaled by the growing optic vesicle once it reaches the overlying surface of the ectoderm.

51

Lens Vesicle

the invagination of the placode by week 5. Shortly after the lens pinches off into the optic cup and becomes the lens. 

52

Myopia

nearsightedness, image focused in front of the retina- distant objects are blurry

53

Hyperopia

farsightedness, image focused behind retina- close objects appear blurry

54

Tympanic Membrane

Thin, translucent membrane that soundwaves hit. TM vibrates and transfers energy to bones of the middle ear.

55

Pharyngotympanic tube

Eustachian Tube. Links middle ear to pharynx. 4 cm long. Normally flat but can be opened during swallowing or yawning to equalize airpressure in the middle ear. 

56

cochlea

Spiraly bony chamber the size of a pea. Where hearing is perceived. Made up of cochlear duct (scala media filled with endolymph), scala tympani and scala vestibuli (filled with perilymph fluid).

57

Equilirbirum

  • measures the position and movement of the head to create balance
  • occurs within the vestibule and the semicircular canals
  • transmits through the vestibular nerve to the lower brain centers (not the cerebral cortex!!)

58

examples of sympathetic nervous system

during vigorous exercise or an emergency situation, the sympathetic nervous system accelerates your heartbeat and breathing rate while dilating the pupils and diverting blood from the skin to more vital organs such as the brain and heart. 

59

examples of parasympathetic nervous system

More active when the body is at rest. Conserves energy, directs vital activities. Heart rate and respiratory rates are at normal low levels, gastrointestinal tract is digesting food,  pupils are constricted as the eyes focus for close vision.

60

Nerves

bundles of peripheral axons

61

ganglia 

clusters of peripheral cell bodies.

62

During embryonic development, the lens of the eye form from what type of epithelia?

63

Ectoderm

64

Taste buds are found:

65

Majority on surface of tongue, but also found on the posterior region of the palate, inner surface of cheeks, posterior wall of pharnyx, and on the epiglottis

66

The gustatory pathway

 

[Image]

67

Dorsal Root Ganglia

a dorsal root of the spine that contains cell bodies of nerve cells (neurons) that carry signals from sensory organs toward the appropriate integration center.

68

Anatomy of cochlea

[image]

69

Structural and Functional Areas of Cerebral Cortex

[Image pg 396]

70

Lobes, sulcui, and fissures of cerebral hemispheres

[image pg 394]

71

Tic Douloureux

Compression of the trigeminal nerve by an adjacent blood vessel causes degeneration and loss of the myelin sheath that surrounds the sensory nerve fibers. Impulses in nerve fiber that carry touch sensations also stimulate pain fibers in the same nerve, leading to perception of pain in the brain from even the softest touch to the face. 

72

A-Iris

B-Pupil

C-Anterior Chamber

D. Optic Nerve

E. Ciliary Muscle

73

A-Superior Rectus

B-Inferior Rectus.


Also pictured: Lateral rectus, tarsal plate/glands, orbicularis oculi muscle, conjunctival sac, bulbar conjuntiva, Palpebrae fissure, cornea, palpebrae conjunctiva.

74

A-semicircular canals

b-cochlea

c. Tympanic membrace

d stapes

 

75

A-Vestibular membrane

B-Tectorial Membrane

C- Scala Media or cochlear duct

D- Scala tympani.

 

Also pictured: Scala vestibuli, stria vascularis, organ of corti, basilar membrane, spiral ganglion.

See pg 501

76

A- Longitudinal Cerebral Fissure. MUCH deeper than a sulcus

B- Temporal Lobe

C- Medulla Oblongata?

77

Brachial Plexus