Psy6105: Bio_O'callaghan_1/31/12_Lecture 2

Front 1

Stroke

Back 1

Interruption of blood to the brain that kills brain cells ad causes neurological symptoms.
• 500K strokes/year in the US; 2nd leading cause of death worldwide

Front 2

Ischemia Stroke

Back 2

Deficiency of blood flow to the brain by clot or some other constriction or obstruction of a blood vessel

Front 3

Hemorrhagic stroke

Back 3

Burst of a blood vessel
• 500K strokes/year in the US;

Front 4

The Brain:
Nuclei

Back 4

Groups of neurons - work together

Front 5

Ipsilateral

Back 5

Structures that lie on the same side

Front 6

Contralateral

Back 6

Structures that lie on opposite sides

Front 7

Bilateral

Back 7

One structure lies in each hemisphere

Front 8

Proximal

Back 8

Structures are close to one another

Front 9

Distal

Back 9

Structures are far from one another

Front 10

Afferent

Back 10

Movement toward the brain
• Sensory pathways

Front 11

Efferent

Back 11

Movement away from the brain
• Motor pathways

Front 12

Dorsal Superior
Ventral Inferior
Rostral Anterior
Caudal Posterior

Back 12

Dorsal Superior: top of brain
Ventral Inferior: bottom of brain

Rostral Anterior: front of brain
Caudal Posterior: back of brain

Front 13

Nervous System Structure

Back 13

Central NS: Brain & Spinal Cord
Somatic NS: Cranial & Spinal Nerves
Autonomic NS: Sympathetic & Parasympathetic Divisions

Front 14

Coronal Section

Back 14

Cutting the brain in a vertical section. (Gives frontal view.)

Front 15

Horizontal Section

Back 15

Cutting the brain in a horizontal section. (Gives dorsal view.)

Front 16

Sagital Section

Back 16

Cutting the brain in a vertical section. (Gives medial view.)

Front 17

4 Ways that the brain and spinal cord are protected: 1

Back 17

1. Skull protects brain; bony vertebrae protect spinal cord
• CNS is protected by bony encasements, but self-repair is limited
• PNS lacks bony protection > more vulnerable to injury; can renew itself after injury by growing new axons/dendrites

Front 18

4 Ways that the brain and spinal cord are protected: 2

Back 18

2. The meninges: triple-layered set of membranes within bony enclosings of CNS
• Dura matter, arachnoid membrane, pia matter

Front 19

4 Ways that the brain and spinal cord are protected: 3

Back 19

Cerebrospinal fluid
• Circulates in four ventricles of the brain, spinal column, and within subarachnoid space
• Cushions brain and spinal cord from shock and sudden pressure changes
• Hydrocephalus: Congenital condition which occurs if outflow of CSF is blocked > severe mental retardation and possible death

Front 20

4 Ways that the brain and spinal cord are protected: 4

Back 20

• Blood-Brain Barrier: prevents intrusion by chemicals and other blood-borne substances from entering CNS tissues

Front 21

Blood Vessels of the Skull

Back 21

• Lie in space between skull and cerebrum; provides blood supply
• Rupture during trauma > bleeding
• Grooves for arteries

Front 22

Blood Supply

Back 22

• Brain requires constant oxygen supply - lack of oxygen for few minutes can > brain damage

Front 23

How many arteries feed the brain and name the two types:

Back 23

4 arteries up each side of the neck:
• 2 internal carotid arteries
• 2 vertebral arteries
Connect at the base of the brain and enter the skull
> branch off into several smaller arteries that irrigate the brainstem and cerebellum > 3 arteries that irrigate forebrain

Front 24

3 arteries that irrigate forebrain:

Back 24

• Anterior Cerebral Artery - irrigates the dorsal
• Middle Cerebral Artery - irrigates the lateral
• Posterior Cerebral Artery - irrigates the ventral

Front 25

How does the brain form?

Back 25

• Stem cell (Self-renewal) >
• Progenitor (Progenitor produced) >
• Blast (Neuroblasts and Glioblasts producted) >
• Specialized (Neuro and Glio differntiations) >

Front 26

Neurons:
Bipolar

Back 26

Bipolar: simple neuron - axon and dendrite on opposite sides

Front 27

Neurons:
Somatosensory

Back 27

Somatosensory: project from sensory receptors > spinal cord, dendrite and axon connected = faster speed of info transmission

Front 28

Neurons:
Interneurons

Back 28

Interneurons: are within brain and spinal cord; link up sensory and motor neurons in CNS; many dendrites, branching axon

Front 29

Neurons:
Motor

Back 29

Motor: in brainstem, project to facial muscles - in spinal cord to other muscles - all bx passes through them

Front 30

Glial Cells

Back 30

All different kinds with different functions

Front 31

Know Glial Cells and Their Functions in Book!!!
(They are for support)

Back 31

Know Glial Cells and Their Functions in Book!!!
(They are for support)

Front 32

Gray Matter

Back 32

Gray-brown color from capillary blood vessels and neuronal cell bodies

Front 33

White matter

Back 33

Axons that extend to form connections with other neurons

Front 34

Reticular matter

Back 34

"Net" or mixture of cell bodies and axons - grey and white matter, netlike

Front 35

Tract/Fiber Pathway

Back 35

Large collection of axons projecting to or away from a nucleus or layer in the CNS
• Carry info from place to place within the CNS
• Ex. corticospinal/pyramidal tract carries info from cortex to spinal cord
• Ex. Optic tract: information from retna of eye to visual centers in the brain

Front 36

Nerves:

Back 36

Fibers and fiber pathways that enter and leave the CNS.
• Ex. auditory nerve, vagus nerve
• After the nerve leaves the CNS, they are called tracts

Front 37

Origin and development of CNS

Back 37

Vertebrate > Mammalian > Human

Front 38

Steps in the development of the brain: Human Brain

Back 38

Retains most features of other mammalian brains but larger cerebral hemispheres

Front 39

Human Brain: Forebrain

Back 39

Neocortex, basal ganglia, limbic system, olfactory bulb, lateral ventricles

Front 40

Human Brain: Brainstem

Back 40

Thalamus, hypothalamus, pineal body, third ventricle, tectum, tegmentum, cerebral aqueduct, cerebellum, pons, fourth ventricle, medulla

Front 41

Cerebral Ventricles

Back 41

• Hollow pockets filled within the brain filled with CSF
• Numbered 1-4
- Lateral ventricles (first and second)
- Third and fourth ventricles extend into the brainstem and spinal cord

Front 42

Spinal Cord Structure & Spinal Nerves

Back 42

• 30 segements
• Cervical
• Thoracic
• Lumbar
• Sacral

Front 43

Dermatomes

Back 43

Regions of body surfaces

Front 44

Dorsal Root

Back 44

• Strand of afferent fibers entering the spinal cord
• Carries sensory information to the brain

Front 45

Ventral Root

Back 45

• Strand of afferent fibers leaving the spinal cord
• Carries motor information to the brain

Front 46

SC Injuries

Back 46

Paraplegic: no control over legs
Quadriplegic: cut is higher on cord - unable to use arms or legs

Front 47

Flexion

Back 47

Stimulation of pain and temperature receptors in limbs produces flexion - limb turns out and away from injury

Front 48

Extension

Back 48

Stimulation of fine touch and muscle receptors > extension
• Extensor reflex - touch part remains in contact with stimulus

Front 49

Cranial Nerves

Back 49

• Make connections between the somatic nervous system (SNS) and CNS
• 12 pairs, overseen by the brain
• Can have afferent functions, efferent functions, or both

Front 50

Cranial Nerves

Back 50

12 of them - Know what they generally do
What does the vagus nerve do?
What does the Sensory nerve do?

Front 51

Autonomic Nervous System

Back 51

Two Divisions:
• Sympathetic
- Arouses the body for action
- "Fight or flight"
- Spinal nerves in the thoracic and lumbar regions are connected to the sympathetic ganglia

• Parasympathetic
- Calms the body
- "Rest and digest"
- Connects with parasympathetic ganglia near target organs

Front 52

The Brainstem

Back 52

• Produces more complex movements than does the spinal cord
• Regulates many complex functions

Front 53

Hindbrain

Back 53

• Cerebellum
• Recticular Formation
• Pons and Medulla

Front 54

Cerebellum

Back 54

• Corrdinates and helps learn skilled movements
• Damage = Equilibrium problems, postural defects, and impairment of skilled motor activity

Front 55

Recticular Formation

Back 55

• Maintains general arousal

Front 56

Pons & Medulla

Back 56

• Waking, sleeping, respiration, cardiovascular functions, locomotion
• Coughing, sneezing, vomiting

Front 57

The Midbrain

Back 57

Two Main Subdivisions
1. Tectum/"roof" - dorsally located - receives sensory info from eyes and ears
2. Tegmentum/"floor" - ventrally located - composed of nuclei related to motor functions

Front 58

Tectum

Back 58

Tectum/"roof" - dorsally located
• Receives sensory info from eyes and ears
• Superior colliculi: mediate visually related bx
• Inferior colliculi: mediate many auditory-related bx
• Both colliculi involved in orienting towards movements (i.e., turning head to look at the source of a sound)

Front 59

Tegmentum

Back 59

Tegmentum/"floor" - ventrally located
• Composed of nuclei related to motor functions
• Red nucleus: controls limb movements
• Substantia Nigra: important for reward and for initiating movements
• Periaqueductal gray matter: cell bodies - controlling species-specific bx (i.e., sexuall bx) and for modulating responses to pain

Front 60

Diencephalon (Know This!!!)

Back 60

• Hypothalamus
• Thalamus
• Epithalamus

Front 61

Hypothalamus (Know This!!!)

Back 61

.3% of brain - but involved in almost all aspects of motivated bx, interacts with pituitary gland

Front 62

Thalamus (Know This!!!)

Back 62

Largest structure in Diencephalon - "Relay Center" of the brain
• 20 large nuclei which each project to a specific area of the cerebral cortex
• Relays info from sensory systems to their appropriate targets: LGB, MGB, VLP
• Relays information between cortical areas
• Relays info from other forebrain and brainstem regions

Front 63

Thalamus related:
Lateral Geniculate Body (LGB)
Medial Geniculate Body (MGB)
Ventrolateral Posterior Nucllei (VLP)

Back 63

Lateral Geniculate Body: receives visual projections
Medial Geniculate Body: receives auditory projections
Ventrolateral Posterior Nuclei: receives touch, pressure, pain, and temperature projections from body

Front 64

Epithalamus

Back 64

Pineal gland - secretes melatonin - influences seasonal body rhythms. Involved in hunger and thirst.

Front 65

Hypothalamus:
Location and what it does

Back 65

Sits under the Thalamus at the top of the brainstem.
• Controls autonomic nervous system
• Center for emotional response and behavior
Regulates body temp
• Regulates food intake
• Regulates water balance and thirst
• Controls sleep-wake cycles
• Controls endocrine system

Front 66

Thalamus:
Location and what it does

Back 66

Sits deep in the brain at the top of the brainstem.
• Called the "gateway to the cerebral cortex"
• Nearly all sensory inputs pass through it to the higher levels of the brain

Front 67

The Forebrain:

Back 67

Basal Ganglia
The Limbic System
The Neocortex

Front 68

Basal Ganglia

Back 68

• Involved in movement
• Collection of nuclei:
- Putamen
- Globus Pallidus
- Caudate Nucleus
• Supports stimulus-response learning
• Sequencing movements
• Diseases of the BG
- Huntington's chorea: progressive cell death in BG > involuntary "dance like" movements
- Parkinson's Disease: projections in the BG die > rigidity, tremors, difficulty with balance
- Tourette's Syndrome: involuntary motorized tics and vocalizations

Front 69

Basal Ganglia & Learning

Back 69

• Supports stimulus-response or habit learning
• Birds ex.: brightly colored butterfly has a bitter taste, so can learn the assoc. between color and taste and refrain from eating
• Flicking a light switch, turning a handle on a door
• Basal Ganglia disorders > difficulty with these stimulus-response actions

Front 70

Limbic System Structures

Back 70

• Hippocampus
• Amygdala
• Septum
• As a system, involved in emoptional and sexual bx, memory, motivation and reward, navigation

Front 71

Hippocampus

Back 71

Mediates memory and spacial navigation
Vulnerable to effects of stress

Front 72

Amygdala

Back 72

Memory, emotional reactions (emotional center of the brain), species typical bx

Front 73

Septum

Back 73

Emotional and species typical bx

Front 74

The Cerebrum: Neocortex

Back 74

• The cerebrum's surface
• The neocortex is convoluted into hundreds of folds.
• Where all the higher brain functions take place

Front 75

The Neocortex: cerebral cortex
Part 1

Back 75

• Thin layer of cells about 1.5 to 4 mm thick
• Provides the connections and pathways for highest cog. functions such as language and abstract thinking
• Contains about 25 billion neurons, 62K mi of axons, etc...

Front 76

The Neocortex: cerebral cortex
Part 2

Back 76

• Has expanded the most during evolution
• Comprises 80% of the human brain
• 2500sq/cm; 1.5 to 4 mm thick
• Six layers
• Two hemispheres, four lobes
• Primary function is to create and respond to perceptions of the world

Front 77

Fissure

Back 77

A cleft in the cortex that is deep enough to indent the ventricles

Front 78

Sulci

Back 78

A shallow cleft in the cortex

Front 79

Gyri

Back 79

A ridge in the cortex