Neurobiology II (Lec 18 - 20) Flashcards
The blood brain barrier forms a layer of protection between the ______ and the ________
Interstitial fluid and the Blood
What is the function of blood brain barrier
isolate body’s main control center from potentially harmful substances
Tight junctions are stimulated by ______ signals which are secreted by ______
Paracrine signals // Astrocytes
Function of Tight Junction ?
prevent solutes from moving between cells ( present in brain capillaries)
(T/F) Typical capillaries (outside of CNS) have tight junctions
False. They have “leaky” capillary walls
How do hydrophobic molecules move across membranes of typical capillaries
They diffuse across the membranes of endothelial cells
How do hydrophilic molecules move across membranes of typical capillaries
They move through “pores” of the capillary
How do macromolecules ( proteins) move through gaps
They are actively transported by transcytosis
Define Transcytosis
Endocytosis = into the cell // exocytosis = outside of the cell
_______ molecules can only cross the blood brain barriers using ______ ( within the CNS)
Hydrophilic using specific transport proteins
How do hydrophobic molecules move across membranes within the CNS
they diffuse across endothelial cells
(T/F) Transcytosis occurs across capillary endothelial cells in the CNS
False. There is not transcytosis within the CNS
How do hydrophilic molecules move across capillary walls in the CNS ? What is the structure responsible for this ?
They move through active transport with specialized protein carriers since there are tight junctions which eliminates pores
(T/F) Specific transport proteins must be present in order for hydrophilic molecules to pass through capillary walls in the CNS.
True.
An example of molecules with no transport protein is ?
catecholamine
Glucose is transported by the specific transport protein
Glut1
Three main parts of the brain
Forebrain, brainstem, cerebellum
Looking at the cerebrum, the left and right hemispheres are separated by the _________ and connected by a bundle of nerve fibers called the _______
Longitudinal fissure and connected by corpus callosum
The cerebrum consists of left and right ________ as well as a deep ________ under the brain
Hemispheres // subcortical nucleui
The cerebral hemispheres consists of the ______
Cerebral cortex
The cerebral cortex is made up of the outer shell of _______ and inner layer of ________
Gray matter / white matter
Gray matter is composed of _______, while white matter is primarily composed of _________
Cell bodies // myelinated fiber tracts
An example of the subcortical nuclei is the ______. They are responsible for ______
basal nuclei. They are responsible for modifying movement
The cerebral cortex is organized in ____ layers
six layers
Convolutions called ____ and _____ are present in the cerebral cortex
gyrus and sulcus
Convolutions allow the brain to have a _________ of cerebral cortex to be accommodated within a give _______
greater volume /// given cranial volume
(T/F) Sensory information passes through the cortex directly
False. Sensory information does not pass through the cortex directly, but acts as an integration center
The cerebral cortex can be divided into which 4 areas ?
Frontal, Occipital, Temporal, Parietal
What is topographical organization
Organization according to structure
The relative size of body parts on a homunculus corresponds to the _____ devoted to the body part
Relative size of cortical area
The central core of the forebrain is formed by the _______ which is composed of the ______ and _____
Diencephalon, which is composed of the thalamus and hypothalamus
The ______ is a cluster of cell nuclei
thalamus
Function of thalamus ?
The thalamus relays sensory information directly to the cerebral cortex, except the sense of smell. It filters sensory information therefore is important for directing attention
Damage in the thalamus can results in ______, which is _______.
Synesthesia. stimulation of one sensory pathway leads to an involuntary experience of the second sensory pathway
Function of Hypothalamus ?
pathways that form the master command of neural and endocrine coordination
Brainstem connects the ______ to the _______ and is composed of the (1)______, (2)-_______, (3)________.
Spinal cord to the brain
(1) midbrain (2) pons (3) Medulla oblongata
All nerve cells that pass through the _______ , ______ and _______ has to pass through the brainstem
Spinal cord, cerebellum, and forebrain
An extremely important part of the brainstem that regulates our sleep wake cycles and consciousness is the _______.
Reticular Formation
What is the function of the cerebellum
The cerebellum sits on top of the midbrain and is important for coordinating smooth movements / coordination/ and balance
What is the pathway for cerebellum and its relation to other parts of the brain.
The cerebellum receives information about movement status from the sensory area of the cortex, brainstem, and spinal cord. It then transmits the information to the cortex from the thalamus enabling the cortex to modify the movement to be as smooth as possible.
The spinal cord is a cylinder of nervous tissue, continuous with the ____________, surrounding by the ___________
lower end of the brain, vertebral column
The spinal cord (containing cell bodies and gray matter) ends at the level _____ vertebra in adults
L2
The spinal cord is composed of the inner core of _______ and outer core of _______
Gray matter, white matter
The spinal cord is divided form superior to inferior into what 5 regions.
Cervical, Thoracic, Lumbar, Sacral, coccygeal
What is the cauda equina? It is also called the ______.
the 1/3 end of the spinal cord where no cell bodies are found. It is also called the horse tail.
The spinal cord gray matter is composed of ____ and shaped like ______
cell bodies (unmylinated) // the letter H
Function of the ventral and dorsal horns
ventral horns are associated with motor neurons
Doral horns are associated with sensory neurons
The spinal cord white matter contains ascending & descending bundles. Function ?
Ascending Bundles carry sensory information to the brain (myelinated)
Descending Bundles commands motor neurons ( myelinated)
Explain Afferent Fibers
Afferent Fibers originate in the periphery and terminate at the dorsal horn.
Cell bodies of the afferent fibers are located at the ______
Dorsal Root Ganglia
Cell bodies of the Efferent neurons are found at the ______
Spinal Cord ( ventral horns)
Function of Efferent neurons
projects axons to the periphery to synapse with effectors
What are ventral roots
efferent limb of each spinal nerve that conducts motor impulses
What are spinal nerves
union of dorsal and ventral roots and are found in intervertabal formation
What does the dorsal column-medial lemniscal pathway relay
Sensory information to the somatosensory cortex
Explain the dorsal column-medial lemniscal pathway
- When you touch a rose pedal, afferent neurons are activated and enter the spinal cord through the dorsal root. This is called First order neurons.
- First order neurons ascend to the end of the dorsal column nuclei in the medulla oblongata and synapse with second -order neurons
- Second order neurons pass through the medial lemniscus on the contralateral side and ascend to the thalamus.
- Third neurons then transmit the information from the thalamus to the somatosensory cortex.
