PNB 2774 EXAM 3

Neurovascular unit

A functional unit composed of groups of neurons and their associated astrocytes, interacting with smooth muscle cells and endothelial cells on the microvessels (arterioles) responsible for their blood supply, and capable of regulating the local blood flow

Choroid plexus

A site of production of CSF in the adult brain. It is formed by the invagination of ependymal cells into the ventricles, which become richly vascularized

Interstitial fluid(ISF).

The extracellular fluid filling the 'interstices' of the tissue, and bathing the cells

Tight junction:

•A belt-like region of adhesion between adjacent cells. Tight junctions regulate paracellular flux, and contribute to the maintenance of cell polarity by stopping molecules from diffusing within the plane of the membrane.

Meninges:

The complex arrangement of three protective membranes surrounding the brain, with a thick outer connective tissue layer (dura) overlying the barrier layer (arachnoid), and finally the thin layer covering the glia limitans (pia). The sub-arachnoid layer has a sponge-like structure filled with CSF.

Receptor-mediated transcytosis

•The mechanism for vesicle-mediated transfer of substances across the cell, the first step of which requires specific binding of the ligand to a membrane receptor, followed by internalization (endocytosis).

Adsorptive-mediated transcytosis:

•The mechanism for vesicle-mediated transfer of substances across the cell, the first step of which involves nonspecific binding of the ligand to membrane surface charges, followed by internalization (endocytosis).

Perivascular endfeet:

•The specialized foot-processes of perivascular astrocytes that are closely apposed to the outer surface of brain microvessels, and have specialized functions in inducing and regulating the BBB.

Pericyte:

•A cell of mesodermal origin, and contractile-phagocytic phenotype, associated with the outer surface of capillaries.

Basal lamina:

•The extracellular matrix layer produced by the basal cell membrane, used as an anchoring and signalling site for cell-cell interactions.

Cranial Meninges

The dura mater,
arachnoid, arachnoid (left), and pia mater.

Dura mater

•Two fibrous layers
.Space between the two layers contains tissue fluids, blood vessels, and lymphatic system

Arachnoid

•Arachnoid membrane: Epithelial layer
•Subarachnoid space
•Does not follow the brain's underlying folds

Pia Mater

•Follow the brain's underlying folds
•Accompanies the branches of cerebral blood vessels

oxygen and glucose In brain supply

•Oxygen
-Passes freely across blood-brain barrier
•Glucose
-Requires membrane transporters
-Brain consumes about half of body's glucose
-Progressive hypoglycemia leads to confusion, unconsciousness, and death

Arteries

•Internal carotid arteries
•Vertebral arteries

Veins

•Internal jugular veins

Blood-Brain Barrier Is composed of?

-Capillary endothelial cells (tight junctions)
-Basal lamina
-Endfeet of astrocytes
-Pericytes(Contractilily; produce angiogenic factors)

Neurovascular unit (NVU)

Role in regulation of regional blood flow and BBB function
composed of:
•Capillary endothelial cells
•Pericytes
•Glial cells
-Astrocyte
-microglial
•Neurons

Brain interstitial fluid vs. Plasma

•Brain interstitial fluid has a
-lower pH (7.33) resulting from a higher pCO2 (50mmHg).
-very low protein content (0.2g/l), resulting in a low buffering capacity.
-lower glucose concentration.
-low K (due to absorption of K into the blood)
-Low HCO3-

From breath to breath, which one of the following will be more subjected to a change in pH?

Disruption of BBB will likely to

Cerebral Spinal Fluid (CSF)

•Around and inside brain and spinal cord
•Cushion and protection
•Maintain chemical stability
Clear waste products

Circulation of CSF

•Produced by choroid plexus in the ventricles
•
•Leaves the 4th ventricle via paired lateral apertures or the single median aperture
•
•Flows through the subarachnoid space
•
•Flows into the arachnoid villi, then drains into the dural venous sinuses

As CSF circulates, CSF and the interstitial fluid of the CNS have been shown to have similar ion concentrations, what kind of movement is involved?

A.osmosis
B.perfusion
C.diffusion
D.active transporter
E.conduction

How does sleep affect CSF circulation?

Glial cells control flow through the glymphatic system by changing their sizes.

The concentration of K+ in brain interstitial fluid is _________ the blood.

A.higher than
B.lower than
C.the same as

If one's blood brain barrier (BBB) is compromised, initially

A.the membrane potential of the effected neurons is more depolarized.
B.the membrane potential of the effected neurons is more hyperpolarized.
C.the membrane potential of the effected neurons remains the same.

amygdala

•Part of the brain's limbic system, this primitive brain structure lies deep in the center of the brain and is involved in emotional reactions, such as anger or fear, as well as emotionally charged memories. It also influences behavior such as feeding, sexual interest, and the immediate "fight or flight" stress reaction that helps ensure the person's needs are met.

Broca's area

•Discovered by French physician Paul Broca in the late 19th century, this small region in the left frontal lobe has been linked to speech production.

central sulcus

The primary groove in the brain's cerebrum, which separates the frontal lobe in the front of the brain from the parietal and occipital lobes in the rear of the brain.

cerebellum:

A brain structure located at the top of the brain stem that coordinates the brain's instructions for skilled, repetitive movements and helps maintain balance and posture. Research suggests the cerebellum may also play a role, along with the cerebrum, in some emotional and cognitive processes

cerebrum:

•The cerebrum is the largest brain structure in humans, accounting for about two-thirds of the brain's mass and positioned over and around most other brain structures. The cerebrum is divided into left and right hemispheres, as well as specific areas called lobes that are associated with specialized functions.
•corpus callosum: The collection of nerve fibers connecting the two cerebral hemispheres.

hippocampus

A primitive brain structure, located deep in the brain, that is critical for memory and learni

hemisphere:

In brain science, refers to either half of the brain (left or right). The two hemispheres are separated by a deep groove, or fissure, down the center. Some major, specific brain functions are located in one or the othe

insula

•Sometimes referred to as the insular cortex, this small region of the cerebrum is found deep within the lateral sulcus, and is believed to be involved in consciousness, emotion, and keeping the body in balance.

limbic system

• A group of evolutionarily older brain structures that encircle the top of the brain stem. The limbic structures play complex roles in emotions, instincts, and appetitive behaviors.

midbrain

Also referred to as the mesencephalon, the midbrain is a small part of the brain stem that plays an important role in movement as well as auditory and visual processing.

motor cortex

: The part of the brain's cerebrum, just to the front of the central sulcus in the frontal lobe, that is involved in movement and muscle coordination. Scientists have identified specific spots in the motor cortex that control movement in specific parts of the body, the so-called "motor map."

occipital lobe

•A part of the brain's cerebrum, located at the rear of the brain, above the cerebellum. The occipital lobe is primarily concerned with vision and encompasses the visual cortex.

parietal lobe

The area of the brain's cerebrum located just behind the central sulcus. It is concerned primarily with the reception and processing of sensory information from the body and is also involved in map interpretation and spatial orientation (recognizing one's position in space in relation to other objects or places

prefrontal cortex

•The area of the brain's cerebrum located just behind the central sulcus. It is concerned primarily with the reception and processing of sensory information from the body and is also involved in map interpretation and spatial orientation (recognizing one's position in space in relation to other objects or places).

prefrontal cortex:

•The area of the cerebrum located in the forward part of the frontal lobe, which mediates many of the higher cognitive processes such as planning, reasoning, and "social cognition"—a complex skill involving the ability to assess social situations in light of previous experience and personal knowledge, and interact appropriately with others. The prefrontal cortex is thought to be the most recently evolved area of the brain.

premotor cortex

•The area of the cerebrum located between the prefrontal cortex and the motor cortex, in the frontal lobe. It is involved in the planning and execution of movements.

sulcus

: A shallower groove on the brain's cerebrum (deeper grooves are called fissures)

temporal lobes

The parts of the cerebrum that are located on either side of the head, roughly beneath the temples in humans. These areas are involved in hearing, language, memory storage, and emotion

visual cortex

The area of the cerebrum that is specialized for vision. It lies primarily in the occipital lobe at the rear of the brain and is connected to the eyes by the optic nerves.

Wernicke's area

A brain region housed in the left temporal lobe, believed to be responsible for the comprehension of speech. The region was first documented by German physician Carl Wernicke, after observing a patient with a lesion in this region who was unable to understand speech

Regions of Human Brain

Cerebrum
-Higher brain functions
-
Diencephalon
-Centers for homeostasis
-
Brainstem
-autonomic centers and reflex centers
-
Cerebellum
-Involve in coordination of movement and much more

Cerebrum lobes

Frontal
-Motor, speech, memory formation, personality, emotion
-
Parietal
-Somatosensory cortex
-
Occipital
-Visual processing and storing visual memories
-
Temporal
-Hearing, speech and language, smell

Frontal Cortex

•Motor Control
•
•Goal Directed Behavior
•
•Planning/organizing strategies
•
•Working memory problem
•
•Problem solving
•
•Inhibitions

Phineas Gage's Case

•Personality Change
•Little self-restraint
Reasoning and capacity to understand and follow social norms changed

Based on the information we have learned, which areas are likely injured? (Choose all that apply)
A.Orbitofrontal Cortex
B.Primary motor Cortex
C.Precentral Gyrus
D.Premotor cortex
E.Ventromedial Prefrontal Cortex

Parietal Lobe

•Senses and integrates sensation(s)
•Spatial awareness and perception(Proprioception - Awareness of body/ body parts in space and in relation to each other)

Temporal Lobe

•Hearing

•Organization/comprehension of language

•Information retrieval(Memory and memory formation)

Occipital Lobe

Processing, integration, interpretation of VISION and visual stimuli

Primary Visual Cortex

Visual Association Area
- Interprets information acquired through the primary visual cortex.

Primary Language Areas

Broca's area
Wenicke's area
Angular gyrus
-Superior edge of temporal lobe
Arcuate fasciculus
-A white matter tract that connects Broca's Area and Wernicke's Area.

Which aphasia is due to the damage to the Wenicke's area?

Arcuate Fasciculus

Allows for coordinated, comprehensible speech.

What is preserved (intact)?
-Auditory comprehension
-Speech articulation

What is affected?
-Repeating heard speech/
Paraphrasing

Due to Jane's chronic seizures, her doctor has to gave her a surgery in which the fibers of the corpus callosum are cut. As a result of this surgery she would likely be unable to:
A) speak?
B) move her left arm?
C) verbally identify an object placed in her left hand?
D) Write down the name of an object in her left visual world using her right hand?
E) recognize written words?
F) touch her nose with her eyes closed?
G) Perform complicated math problems presented in her left visual world?

What function(s) might have been affected? (Choose all that apply)

A) speak
B) move her left arm
C) verbally identify an object placed in her left hand
D) Write down the name of an object in her left visual world using her right hand
E) recognize written words
F) touch her nose with her eyes closed
G) Perform complicated math problems presented in her left visual world

transection of the corpus callosum will affect the following functions?

A)verbally identify an object placed in the right hand
B)Write down the name of an object in her left visual world using her right hand
C)Perform complicated math problem
D)touch her nose with her eyes closed
E)All of the above

Brain Lateralization

•Cerebral dominance
-Left: language, math, logic
-Right: spatial abilities, face recognition, visual imagery, music

basal ganglia (basal nuclei):

•A group of structures below the cortex involved in motor, cognitive, and emotional functions.

brain-derived neurotrophic factor (BDNF

•Sometimes referred to as "brain fertilizer," BDNF is a protein that helps promote the growth, maintenance, and survival of neurons.

hypothalamus

•A small structure located at the base of the brain where signals from the brain and the body's hormonal system interact. hemisphere.

limbic system

•A group of evolutionarily older brain structures that encircle the top of the brain stem. The limbic structures play complex roles in emotions, instincts, and appetitive behaviors.

medulla oblongata

The lower part of the brain stem, responsible for life-regulating functions like breathing and heart rate.

Parkinson's disease

A neurodegenerative disorder characterized by tremor, slowed movement, and speech changes due to the death of dopamine neurons located in the substantia nigra

pituitary gland

•An endocrine organ at the base of the brain that is closely linked with the hypothalamus. The pituitary gland is composed of two lobes, the anterior and posterior lobes, and secretes hormones that regulate the activity of the other endocrine organs in the body.

spinal cord

The "other half" of the central nervous system (with the brain). The spinal cord is a cable that descends from the brain stem to the lower back. It consists of an inner core of gray matter surrounded by white matter

striatum

: A small group of subcortical structures, including the caudate nucleus, putamen, and nucleus accumbens, located in the midbrain. These regions are implicated in both movement and reward-related behaviors

substantia nigra

•This small region in the midbrain is part of the brain's reward system. In Parkinson's disease, the dopamine neurons in this region die off, leading to the disorder's movement-related and cognitive symptoms.

subthalamic nucleu

•A small brain structure, located in the basal ganglia, that plays an important role in coordinating movement. It is the most common target for neuromodulation techniques, like deep brain stimulation, to help diminish the symptoms of Parkinson's disease.

thalamus

A brain structure located at the top of the brain stem, the thalamus acts as a two-way relay station, sorting, processing, and directing signals from the spinal cord and midbrain structures to the cerebrum, and from the cerebrum down.

Basal Ganglia (Basal Nuclei)

Forebrain & Midbrain structures that link complex motivational signals to motor function

1.Caudate nucleus
2.Putamen
3.Globus pallidus
4.Claustrum
5.Amygdaloid body

Basal Ganglia (Basal Nuclei)

•Considered as a "side loop"
-Subconscious
•Receive input from entire cerebral cortex and thalamus
•Output to Cerebral Cortex through thalamus
•Modulate motor output
.Prevent unwanted movement!

Read Neural Circuit Diagrams

•Flow of information and brain regions involved
•Nodes: brain regions or individual neurons
-Circles
•Line caps: axonal connections
-Arrows with pointed heads (green): excitable connections
-Arrows with flat heads (red) - inhibitory connections

Movement Related Basal Nuclei

Direct pathway
(Excitatory)


Indirect pathway
(Inhibitory)

Sensory Related Basal Nuclei

•Claustrum
-Seat of Consciousness?
-A conductor of the brain?
•Amygdala
-Emotion/Mood

Diencephalon

Epithalamus
Posterior/Superior

Thalamus
Superior

Hypothalamus
Inferior/Anterior

Diencephalon: Epithalamus

Pineal gland: secretes melatonin, a hormone that helps regulate day night cycles (circadian rhythm).

Diencephalon: Thalamus

•Sensory impulses from all conscious sense converge on the thalamus
-Except olfactory sense
•Principal and final relay for all sensory information
•Efficient filter

Diencephalon: Hypothalamus

•Master control of the autonomic nervous system.
•
•Regulates many homeostatic mechanisms throughout the entire body.

How does the hypothalamus function as the "master regulator" of many homeostatic processes?

Hypothalamus

•Master control of the autonomic nervous system.
•Master control of the endocrine system.
•Regulation of body temperature.
•Control of emotional behavior.
•Control of food intake.
•Control of water intake.
•Regulation of sleep-wake (circadian) rhythms.

structure of limbic system?

•Shape of a ring (around diencephalon)
-Cingulate gyrus
-Hippocampus
-Parahippocampal gyrus
-Amygdala
-Olfactory bulbs
-Fornix
-Diencephalon nuclei

Limbic System - Functions

•Emotional brain
-Emotional and motivational aspects of behavior.
-Provides emotional component to learning process:
•Especially the amygdala.
•Associated with memory
-Especially the Hippocampus.

Brainstem

1.Midbrain (Mesencephalon)
2.Pons
3.Medulla
•
bidirectional passageway for all tracts extending between the cerebrum and the spinal cord

Midbrain

Superior Colliculus
•Vision reflex center
Inferior Colliculus
•Auditory reflex center
Red nucleus
•Gait in animals
•Upper arm and shoulder in humans

Pons and Medulla

Pons
Autonomic respiratory centers

Medulla

Centers for cardiovascular regulation and respiratory rhythm generation

Cerebellum

•Comparison of intent and action (ie., errors)
•impairs motor function on the ipsilateral side of the body (suggest double crossing)

cerebellum function

Key cerebellar motor functions
1. Adjust the postural muscles of the body
2. Error correcting during movement
3. Motor learning and adaptation
4. Automating and optimizing behavior

Which side of cerebellum is affected?(look at slide 23)

breakdown of cerebellum

Spinocerebellum
-Vermis and paravermis
-Motor execution
-Vermis:
•Trunk movement
-Paravermis:
•limbs movement

Vestibulocerebellum
-Input from brainstem vestibular nuclei
-Eye & head movements; balance

Cerebrocerebellum
-Lateral hemispheres
-Motor planning
-Perhaps sensory, cognitive, affective processing(non-motor functions)

Spinal Cord Overview

•Information integration center
•Reflex arcs outside of the brain
•Foramen magnum to 2nd lumbar vertebrate
•Shorter than vertebral column
•31 pairs of nerves exit via intervertebral foramina
Diameter greatest at top

As a doctor, you need to obtain a sample of CSF for diagnose purposes. What would you the sample?

A)Arachnoid mater
B)Epidural space
C)Cerebral ventricles
D)Central Canal
E)Subarachnoid space of the spinal cord

If the dorsal root of a spinal nerve is severed,

A) Output to skeletal muscles would be blocked
B) Output to visceral organs would be blocked
C) the spinal cord would not be able to process information at that level
D) The brain would not be able to communicate with that level of the spinal cord
E) Sensory input would be blocked

What if the dorsal ramus of a spinal nerve is severed?

A) Both sensory and motor information from the back would be blocked
B) Motor output to visceral organs would be blocked
C) The spinal cord would not be able to process information at that level
D) The brain would not be able to communicate with that level of the spinal cord
E) Only sensory input would be blocked