3-Cellular And Gross Anatomy Of Brain

Front 1

Neurons or...and _____ are the types of cells that make up the nervous system

Back 1

nerve cells
glial cells- provide support for neurons

Front 2

How many neurons and glial cells does brain have?

Back 2

100 billion neurons and 1 trillion glial cells

Front 3

how many synapses per neuron? how many in total?

Back 3

5000 synapses that act as input!
10^5 in total

Front 4

brain is ___ of body weight, but consumes __ of body's ___ and ___ of its ___

Back 4

Brain is only 2% of body weight, but consumes 25% of body's oxygen and 70% of its glucose.

Front 5

What are the zones of the Neuron?

Back 5

4 Zones.
1. Input Zone
2. Integration Zone
3. Conduction Zone
4. Output Zone

Front 6

Input Zone

Back 6

neuron receives input from other cells (electrical signal/neurotransmitter) through the region of DENDRITES

Front 7

Integration Zone

Back 7

the region of the cell body or soma where the INPUTS (signals) are combined and transferred.

Front 8

Conduction Zone

Back 8

Every neuron has ONE axon that leads away from the cell body to the terminals to TRANSMIT the electrical impulse
*the combined signal (threshold reached) is the output which is conducted down the axon that transmits this output

Front 9

Output Zone

Back 9

region of the axon terminals at the end of the axon that (transmits the signal (OUTPUT) to other neurons)
Communicates activity to other cells.

Front 10

What is the Neuron Doctrine?

Back 10

19th Century idea proposed by Cajal that the fundamental unit of the brain is the neuron, or nerve CELL.

Front 11

Camillo Golgi

Back 11

Use the Silver or Golgi stain to visualize the fundamental unit of the brain, the neuron.
He proposed the RETICULAR THEORY stating that everything in the Nervous System, such as the brain, is made up a single interlinking network, rather than many integrated units.

Front 12

Santiago Cajal

Back 12

Also visualized the neuron with the Golgi Stain but proposed the NEURON DOCTRINE that states that the brain is made up a of many integrated units

Front 13

Location of neuronal communication?

Back 13

across synapses at the dendritic spines of postsynaptic neuron

Front 14

What is a synapse?

Back 14

A gap between presynaptic axon terminal and postsynaptic dendritic spine.
Each synapse has three components :
1. Presynaptic Membrane: on the axon terminal of presynaptic neuron.
2. Synaptic Cleft- gap that separates the two membranes.
3. Postsynaptic Membrane: on the dendrite or cell body of the postsynaptic neuron.
So synapse includes the output, space, and input region

Front 15

Steps in Synaptic Communication

Back 15

1. Threshold reached, and signal conducted down axon to axon terminals.
2. Electrical signal causes release of synaptic vesicles filled with neurotransmitter by fusion with presynaptic membrane. into the synaptic cleft.
3. Neurotransmitters in synaptic cleft act as keys to postsynaptic neurotransmitter receptors on postsynaptic membrane.
4. Activated post membrane neurotransmitter receptors open to allow ion flow through postsynaptic channels (either receptors or separate channels) into the postsynaptic dendritic spine causing graded potentials that will sum at the axon hillock to potentially pass threshold and excite a signal.

Front 16

What are the glial cells and the types?

Back 16

Glial cells provide support for the neurons and neuronal activity
1. Astrocytes
2. Oligodendrocytes
3. Microglial cells
4. Ependymal Cells
5. Schwaan and Satellite Cells

Front 17

Astrocyte

Back 17

Found in CNS: Star shaped cells with many processes (arms) that receive neuronal input and monitor activity

Front 18

Oligodendrocytes

Back 18

Provide myelination to CNS cells

Front 19

Microglial cells

Back 19

or microglia are small cells that remove debris from injured cells in the CNS

Front 20

Ependymal Cells

Back 20

ependymal cells create the thin epithelium-like lining of the ventricular system of brain and spinal cord and is involved in production of cerebrospinal fluid.

Front 21

Schwaan Cells

Back 21

provide myelination to PNS cells

Front 22

Satellite Cells

Back 22

cells that cover surface of nerve cell bodies in PNS cells

Front 23

Myelination

Back 23

the process by which glial cells (oligodendrocytes and Schwaan cells) wrap axons in a fatty sheath or myelin for insulation and speed conduction.

Front 24

Multiple Sclerosis

Back 24

A disease that causes demyelination

Front 25

difference between oligodendrocyte and Schwaan cell?

Back 25

Oligo in CNS and can wrap many segments of axons and of different neurons
Schwaan in PNS and wraps only one segment of one neuron.

Front 26

what is a neuronal circuit?

Back 26

functional entity of interconnected neurons that is able to regulate its own activity using a feedback loop

Front 27

Anatomical Division of Nervous System

Back 27

* all the nerve fibers radiating out beyond the brain and spinal cord as well as all the neurons outside the brain and spinal cord form the PNS
so PNS defined as neurons and nerve processes outside the CNS

Front 28

what encases the CNS

Back 28

skull encases brain,
and vertebra encase spinal cord

Front 29

What are the divisions of the ANS, and what is it?

Back 29

ANS stands for Autonomic Nervous System, is a branch of the PNS that is not voluntary and is divided into
1. Sympathetic Nervous System- controls the flight or fight response
2. Parasympathetic Nervous System- active during relaxed, non-dangerous situations.
3. Enteric Nervous System- controls digestions

Front 30

Define Homeostasis in terms of neuroscience

Back 30

is the dynamic balance between the autonomic branches ( sympathetic and parasympathetic nervous systems)

from rest, digest to flight or flight

Front 31

Somatic Nervous System

Back 31

the branch of the PNS that encases voluntary control of body movements through skeletal muscles

Front 32

Types of Directional Neuronal information flow

Back 32

1. Sensory/Incoming (Afferent Pathways) - sensory information coming into the CNS
2. Motor/ Outgoing (Efferent Pathways)- information leaving the CNS

processing center is CNS

Front 33

Brain Anatomy : brain surface

Back 33

The brain is split into two cerebral hemispheres. The outermost layer of these hemispheres is the cerebral cortex. The cerebral cortex is convoluted (more surface area). The raised regions are called gyri (gyrus) and the farrows are called sulcus (sulci)

Front 34

Where is the central sulcus and sylvan fissure?

Back 34

Central sulcus separates the Frontal and Parietal lobe, and the pre central gyrus and post central gyrus .

The Sylvian Fissure separates the Temporal Lobe from the Frontal and Parietal Lobes.

Front 35

What are the four lobes of the brain and their functions

Back 35

Frontal - functions in impulse control, decision making, and contains the motor cortex

Parietal - contains the somatosensory cortex (processes pain, touch and temperature)

Occipital- functions in visual processing, visual cortex

Temporal - functions in auditory processing and memory

Front 36

What are meninges?

Back 36

The 3 membranes ( the dura mater, arachnoid membrane and pia mater) that line the skull and vertebral column, surrounding and protecting the brain and spinal cord.

Front 37

layers of the meninges from skull to brain

Back 37

Front 38

where does the Cerebrospinal Fluid circulate and what is it's function?

Back 38

in spinal cord- the central canal
in brain - in ventricles and subarachnoid space of meninges

Function of CSF-
1. provides an exchange medium between the blood and brain.
2. acts as shock absorber

so CSF found around and inside the brain.

Front 39

what is Ventricular System and how many are there?

Back 39

the ventricular system is a series of chambers in the brain filled with cerebrospinal fluid

the two lateral ventricles, and the third and fourth ventricles.

Front 40

Types of matter in the brain and where is each found?

Back 40

"types" of matter represents the color of the two types of brain tissue.
1. White Tissue (matter) - consists of mostly axons with white MYELIN sheaths
2. Grey Tissue (matter)- contains mostly cell bodies and dendrites, which LACK MYELIN

cerebral cortex- grey
inside- mostly white

so connections are inside the network

Front 41

what is the neocortex

Back 41

neocortex, or cortex is part of the cerebral cortex and has 6 distinct layers distinguished by
1. type of neuron in layer
2. pattern of dendrites or axons.

Front 42

what is the cerebral cortex

Back 42

the outermost layer of convoluted grey matter that covers the internal parts of the cerebrum (brain)

Front 43

What are the functions of the layers of the cerebral cortex?

Back 43

layer 4- receives sensory input (afferent pathways)
layers 1-3: integrative funcitons
layers 5/6: outputs to other parts of brain (efferent)

* this means the grey matter does the processing and white matter communicates this information to different parts of the brain.
why the lowest layers are output ,near the white matter

Front 44

What is an application of the different layers of the neocortex?

Back 44

Cytoarchitectonic Maps- Brodmann defined brain areas by characteristics and organization of cells