Chapter 3 (The Cns - The Brain)

Front 1

CNS consists of the

Back 1

brain and spinal cord

Front 2

Peripheral nervous system (PNS) consists of

Back 2

nerve fibres that carry information between the CNS and peripheral parts of the body

Front 3

What is afferent division?

Back 3

carries information/instructions from peripheral body parts to CNS

Front 4

What is efferent division?

Back 4

carries information AWAY from CNS to effector organs (muscles and glands)

Front 5

Efferent division is divided into:

Back 5

1. somatic nervous system: consists of fibres of motor neurons that supply skeletal muscles

2. autonomic nervous system: consists of fibres that innervate smooth muscle, cardiac muscle and glands

Front 6

The autonomic nervous system has two divisions

Back 6

1. Sympathetic NS

2. Parasympathetic NS

Front 7

Sympathetic NS

Back 7

prepares body for stressful, emergency or energetic activities such as fight or flight

Front 8

Parasympathetic NS

Back 8

dominates during times of "rest and repose" - directs maintenance activities

Front 9

Afferent neurons

Back 9

inform CNS about conditions in both external and internal environment

Front 10

Efferent neurons

Back 10

carry instructions from CNS to effector organs - muscles and glands

Front 11

Interneurons

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found entirely within CNS and responsible for:

- integrating afferent information and formulating an efferent response

- higher mental functions associated with the mind

Front 12

Glial cells form most of

Back 12

the brain tissue

Front 13

4 types of glial cells, briefly describe each

Back 13

1. astrocytes: help form the blood-brain barrier

2. Oligodendrites: form sheaths around axons in CNS

3. Microglia: act like white blood cells to clear the brain of microbes/antigens

4. Ependymal cells: help form choroid plexes of ventricles for the formation of cerebrospinal fluid (CSF)

Front 14

4 major feature that protect the CNS from injuries, briefly describe each:

Back 14

1. Meninges: wrap, protect and nourish the membranes

2. cerebrospinal fluid (CSF): floating and cushioning fluid of the brian

3. Blood-brain barrier (BBB): access limiting barrier to blood born material to the brain

4. Cranium: Bony case that encloses the brain and spinal cord

Front 15

3 parts of the meninges:

Back 15

1. dura matter

2. arachnoid matter

3. pia matter

Front 16

Location and function of dura matter

Back 16

outermost, double, tough, inelastic membrane that forms dura and venous sinuses

Front 17

Location and function of arachnoid matter:

Back 17

middle, vascularized, - CSF is reabsorbed across the surfaces of these villi into blood circulating within the sinuses

Front 18

Location and function of pia matter:

Back 18

innermost, fragile membrane, highly vascularized - is closely attached to the surface of the brain and spinal cord

Front 19

Cerebrospinal fluid (CSF) function (2)

Back 19

- surround, protect and cushion the brian and spinal cord

- serve as "shock absorbing fluid"

Front 20

Composition of CSF (3)

Back 20

- produced by choroid plexus (CP consists of vascularized masses called ependymal cells)

- selective transport mechanisms across the membranes of the choroid plexuses forms the CSF

- composed of lower K+ ions than plasma

Front 21

After circulating through the upper region of the brain, CSF reabsorbed into the ______ ________ through ________ ________

Back 21

venous blood, through arachnoid villi

Front 22

Defects in CSF formation, circulation and reabsorption leads to

Back 22

hydrocephalus - increase in CSF pressure and can lead to brain damage and mental retardation

Front 23

Flow of CSF

Back 23

formed in (lateral) first, second and third ventricles -> circulates around brain and spinal cord -> exits at 4th ventricle at base of brain -> flows in subarachnoid space -> reabsorbed into venous blood at arachnoid vili

Front 24

BBB (2)

Back 24

- carefully regulates exchanges b/w the blood and brain

- protect the brain from chemical fluctuation in the blood and prevent harmful blood-borne substances from entering brain

Front 25

Brain capilaries are equipped with

Back 25

tight junction

Front 26

What can be easily transported across the brain capillaries? (4)

Back 26

- Oxygen

- Carbon dioxide

- alcohol

- steroids

Front 27

What molecules are transported by selective transport mechanisms in the brain? (3)

Back 27

glucose, amino acids, ions

Front 28

Disadvantages of the BBB(2)

Back 28

1. BBB limits the use of drugs for treatment of brain and spinal cord disorders

2. prevents certain neurotransmitters from reaching brain

Front 29

Cerebrum

Back 29

- largest portion of the brain, divided in two halves (right and left cerebral hemispheres)

Front 30

What separates the two hemispheres of the cerebrum? what is its function?

Back 30

-corpus callosum - information superhighway of the brain (serves as communication b/w hemisphere

Front 31

Cerebral cortex (3)

Back 31

- thin outer shell of gray matter of each hemisphere

- it is composed of a thick central white matter

- also contains basal nuclei within white matter

Front 32

Cerebral cortex contains 4 lobes

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1. frontal

2. parietal

3. occipital

4. temporal

Front 33

Functions of the 4 cerebral cortex lobes:

Back 33

1. occipital: intial processing of visual info

2. temporal: contains primary auditory cortex and part of limbic association area for motivation, emotion and memory

3. parietal: receive and process sensory info

4. frontal: voluntary motor activity, speaking ability and elaboration of thought

Front 34

Function of basal nuclei (4)

Back 34

- inhibition of tone throughout the body

- selection and maintenance of purposeful activities

- help in monitoring and coordinating sustained contractions related to posture and support

- produces neurotransmitter dopamine

Front 35

Diancephalon - thalamus (4)

Back 35

- serve as relay center and synapsing integration center for sensory inputs to cortex

- routes important impulses to appropriate areas of the somatosensory cortex

- has ability to direct our attention to stimuli of interest

- is capable of creating awareness of various types of sensation

Front 36

Diancephalon - hypothalamus (4)

Back 36

- integrating center for many important homeostatic functions

- serves important link between the ANS and endocrine systems

- directly regulate the internal environment

- extensive involvement in emotion and basic behavioural patterns

Front 37

The hypothalamus is the

Back 37

brain area most involved in directly regulating internal environment

Front 38

What is the limbic system?

Back 38

composed of separate structures that surround the brainstem and interconnected by intricate neuronal pathways

Front 39

Limbic system includs:

Back 39

portions of the hypothalamus and other forebrain structures that encircle the brain

Front 40

Limbic system is responsible for (3)

Back 40

- emotion

- basic, inborn behavioural patterns related to survival and perpetuation of the species

- plays important role in motivation and learning

Front 41

Brainstem consists of

Back 41

- consists of pons, medulla oblongata and midbrain

Front 42

Brainstem function (4)

Back 42

- vital link b/w spinal cord an higher brain centers

- passes all incoming/outgoing fibres of peripheral and higher brain centers

- centers in brainstemcontrol heart, blood vessels, respiration and digest activities

- modulate the sense of pain

Front 43

Pons:

Back 43

- located on inferior surface of the brain (b/w midbrain and M.O)

Front 44

Several nuclei of the pons is associated with nerves such as (3) briefly describe

Back 44

1. trigeminal nerve (V) - impulses for chewing ad sensory sensation from head

2. abducens nerve (VI) - transmit impulses for facial movements and taste buds

3. facial nerve (VII) - control movement of the eyeball and maintains equilibrium

Front 45

Medulla oblongata: (2)

Back 45

- is inferior portion of brainstem

- nuclei and white matter forms the descending/ascending tracts communicating b/w spinal cord and various parts

Front 46

3 major functions of the medulla oblongata

Back 46

1. Cardiac center: bot inhibitory and accelerating impulses travel through vagus nerve to elevate heart rate

2. Vasomotor center: nuclei of this center send the impulses to the smooth muscle of the arterial wall to constrict and elevate the blood pressure

3. Respiratory center: control rate/depth of breathing - work together with respiratory nuclei of the Pons

Front 47

Cerebellum

Back 47

- is attached to the back of the upper portion of the brainstem and lies underneath of occipital lobe

Front 48

Functions (3) of cerebellum?

Back 48

1. maintenance of balance

2. enhancement of muscle tone

3. coordinating and planning of skilled voluntary muscle activities

Front 49

3 parts of the cerebellums

Back 49

1. vestibulocerebellum - maintain balance and crontrol eye movements

2. spinocerebellum - enhances muscle tone, coordinated skilled and voluntary movements

3. cerebrocerebellum - plays role in planning & initiating of voluntary activity by providing input to the cortical motor areas

Front 50

Reticular formation

Back 50

- widespread network of interconnected neurons that spread throughout the entire brainstem and into thalamus

-

Front 51

Reticular formation consists of

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ascending and descending fibres that carry signals upward to arouse and activate cerebral cortex

Front 52

Reticular Activating System (RAS)

Back 52

controls the overall degree of cortical alertness and direct the attention

Front 53

Centers with RAS as responsible for?

Back 53

Sleep