Human Physiology: Central Nervous System

Which brain regions participate in the The Motor Circuit?

Motor cortex, basal nuclei, and other brain regions.

Name three different tissues or organs that are innervated (supply with nerves) by Autonomic Motor Neurons.

Smooth muscles Cardiac muscles Glands

Where within the brain are the BASAL NUCLEI (aka basal ganglia) located? What body functions are they involved in?

Structures of the cerebrum that contain the cell bodies of higher order neurons involved in the control of skeletal muscles.

True or False? NMDA receptors are constantly blocked by extracellular Mg2+ at the resting membrane potential.

True

The walls of the embryonic Neural Tube will become the different regions of the adult human __________________.

brain and spinal cord.

Which specific brain areas are involved in SPEECH?

Broca's area, Wernicke's area, and motor cortex. (left hemisphere)

The primary motor cortex is located anterior to the ____________ sulcus.

central

The sensory area of the cortex is located posterior to the _____________ sulcus.

central

The outer layer of the ____________________ is known as the cerebral cortex.

cerebrum

Interpretation of auditory sensations is performed by the _________________ lobes.

temporal

The cavity (i.e., lumen) within the embryonic Neural Tube will become the ____________________ in the adult brain and the _____________________ in the spinal cord.

ventricles, central canal

Which type of glial cell in the brain forms the blood-brain barrier?

Astrocytes

Which structures in the adult human body are formed by Neural Crest Cells?

Sensory ganglia (dorsal root ganglia)

Name four (4) different types of GLIAL CELLS found within the CNS.

1. Astrocytes: form blood-brain barrier. 2. Oligodendrocytes: form myelination 3. Microglia: are mobile & eat invaders and debris. 4. Ependymal cells: lines the ventricles & forms choroid plexuses.

List three (3) functions of cerebral spinal fluid (CSF).

1. Shock absorption 2. Supplies nutrients 3. Removes wastes produced by metabolic processes within brain cells.

The number of neurons in the adult human brain is estimated to be ___________________.

100 billion

The adult human brain receives about __________ % of cardiac output.

15%

Approximately HOW MANY different structures or regions of the human brain are labelled in SLIDE #14?

19

What percentage of cells in the brain are neurons?

20%

The adult human brain weighs approximately ____________.

3 - 3.5 lbs

What percentage of cells in the brain are glial cells?

80%

What are Dorsal Root Ganglia? Where are they located?

A group of neural cell bodies or somata of sensory neurons. They are located on the outside of the spinal cord, on each side, at each body segment.

What is long-term potentiation? What role is thought to play in memory formation?

A key cellular mechanism of learning and memory. Potentiation: is a process by which synaptic connections between neurons become stronger with frequent activation. LTP is thought to be a way in which the brain changes in response to experience, and thus may be an mechanism underlying learning and memory.

What are the significances of the thin neck and the relatively expanded head region of dendritic spines?

Because the spine neck is narrow it somewhat isolates the head from the dendrite, this isolation may be important in storing memories.

The outer surface of the brain is bathed in a fluid known as: ___________-____________ ____________.

Cerebro-Spinal Fluid (CSF) In Light Blue

The ventricles of the brain, and the central canal of the spinal cord are both filled with _____________-____________ ____________.

Cerebro-Spinal Fluid (CSF) In Light Blue

The anatomical structures that produce CSF are known as ________________ _______________.

Choroid Plexuses: thin, highly vascularized, transporting epithelial structures that protrude into the ventricles.

What is the limbic system? What does it do? What brain structures are considered to be part of it?

Consists of particular nuclei and axon tracts of the cerebrum that cooperate in the generation of emotions. The amygdala and the hippocampus both participate in the limbic system.

Through which process is CSF thought to be created?

Secretion: and is constantly reabsorbed into the venous blood system to maintain a healthy intracranial pressure within ventricles.

Which of the three layers of cells (above) will role up into a tube to become the nervous system?

Ectoderm

A 22-day old human embryo consists of three layers of cells: what are they?

Ectoderm: (the layer on top) will become the nervous system. Mesoderm: Endoderm.

What does an Electro-Encephalo-Gram (EEG) show? What do the signals represent?

Electrical activity produced by the brain. Picking up different types of waves in EEG recordings. These waves vary in amplitude (their height) and frequency (how rapidly they occur).

From which embryonic tissue layer does the Anterior Pituitary gland form?

Endoderm: formed from the roof of the embryonic mouth.

Which type of glial cell in the brain lines the ventricles, and forms choroid plexes?

Ependymal cells

What are the different types of memory? How long does each type last?

Episodic memory: Minutes to years. Semantic memory: Minutes to years. Procedural memory: Minutes to years. Working memory: Seconds to minutes.

What is a sulcus?

Furrows or depressions

What are glutamate receptors, NMDA receptors, and AMPA receptors?

Glutamate: (an amino acid) is the most abundant excitatory neurotransmitter in the vertebrate brain. NMDA: a type of glutamate receptor that conduct both Na+ and Ca2+ into neurons. AMPA: a type of glutamine receptor that conduct only Na+ but not Ca2+ into neurons.

What kinds of ions do each of the glutamate receptors conduct?

Glutamate: (an amino acid) is the most abundant excitatory neurotransmitter in the vertebrate brain. NMDA: a type of glutamate receptor that conduct both Na+ and Ca2+ into neurons. AMPA: a type of glutamine receptor that conduct only Na+ but not Ca2+ into neurons.

In the brain, why does gray matter appear gray, and white matter appears white?

Gray matter: it is not white because it is not myelinated. White matter: it is white because it is myelinated.

Which specific brain structure is thought to play a key role in memory formation?

Hippocampus

Which region of the brain controls body temperature, water balance, hunger, satiety, circadian rhythms and reproduction?

Hypothalamus

Into which specific cavity within the brain do the Choroid Plexuses protrude?

Into the ventricles

What are dendritic spines? What are they the anatomical site of? How many spines does a neuron have?

Is a small protrusion from a neuron's dendrite that typically forms a synapse with one or more presynaptic terminals of other neurons. Within the Hippocampus 10,000 spines

What is the Corpus Callosum?

Is composed of myelinated nerve tracts that are running from one hemisphere to the other, and they're allowing communication between the two hemispheres of the brain.

Why is it important that NMDA (glutamate receptor and ion channel found in neurons) receptors become unblocked?

It allows Ca2+ to enter the postsynaptic cell, then inserts new AMPA receptor in the cell membrane, increasing the cells sensitivity to glutamate

Name a pre-synaptic effect of LTP.

LTP: may also involve an increase in the amount of glutamate secreted by the presynaptic neuron.

Which type of glial cell in the brain eat invaders and debris?

Microglia

What function does an Autonomic (involuntary) Motor Neuron perform?

Nerve that stimulates contraction (or inhibits contraction) of smooth muscle and cardiac muscle and that stimulates glandular secretion.

What function does a Somatic (voluntary) Motor Neuron perform?

Nerve that stimulates contraction of skeletal muscles.

What is the difference between a NERVE and a nerve TRACT?

Nerve: Cable-like collection of many axons in the PNS; may be "mixed" (containing sensory and motor fibers) Tract: Grouping of axons that interconnect regions of the CNS. Nerves = PNS Tract = CNS

Precisely where in the 22-day human embryo do Neural Crest Cells form?

Neural crest cells are isolated following tube formation. They migrate and become a wide variety of structures within the adult body.

What function does a Sensory Neuron (afferent neuron) perform?

Neuron that transmits impulses from a sensory receptor into the CNS.

Which retrograde messenger is involved in LTP?

Nitric Oxide (NO) Long-term potentiation (LTP) is a process involving persistent strengthening of synapses that leads to a long-lasting increase in signal transmission between neurons.

What is the difference between a NUCLEUS and a GANGLION?

Nucleus: Grouping of neuron cell bodies within the CNS. Ganglion: Grouping of neuron cell bodies outside the CNS.

Which type of glial cell in the brain forms myelination of axons?

Oligodendrocytes

What event removes the magnesium block of NMDA receptors?

Postsynaptic membrane depolarization.

What does LATERALIZATION mean?

Refers to the fact that the right and left cerebral hemispheres have different functions.

What is a gyrus?

Ridges

Name the six different types of Neuroglial Cells, and describe their functions.

Schwann cells: produce the myelin sheaths around the myelinated axons of the peripheral nervous system. Satellite cells: support functions of neurons within sensory and autonomic ganglia. Oligodendrocytes: Form myelin sheaths around central axons, producing "white matter" of the CNS. Microglia: Phagocytose pathogens and cellular debris in the CNS. Astrocytes: Cover capillaries of the CNS and induce the blood-brain barrier. Ependymal cells: Form the epithelial lining of the brain cavities (ventricles) and the central canal of the spinal cord; cover tufts of capillaries to form choroid plexuses - structures that produce CSF.

What type of tissue is innervated by a Somatic Motor Neuron?

Skeletal muscles

What is the relationship between the Hypothalamus, and the Posterior Pituitary gland?

The posterior pituitary gland is an extension of the hypothalamus.

What is the STRUCTURE (anatomy) of a Choroid Plexus?

Thin, highly vascularized, transporting epithelial structures that protrude into the ventricles. Consists of a simple cuboidal or columnar epithelium associated with blood capillaries containing a fenestrated endothelium.

Why would anyone get a corpus callostomy?

This surgery has been used to reduce seizures in medically refractory epilepsy.

Why is the surface of the cerebral cortex FOLDED?

To create more surface area of cerebral cortex that can fit inside your skull, because the size of the skull in a human infant that's being delivered vaginally during birth is limiting. gyri (ridges) and sulci (furrows) create the folded appearance.

Personality and decision making are performed by the _______________ lobes.

frontal

Voluntary control of skeletal muscles performed by the ________________ lobes.

frontal

The cerebral hemispheres are divided into _____________ lobes, _____________ lobes, _______________ lobes and ________________ lobes.

frontal, parietal, occipital, temporal

The HYPOTHALAMUS contains numerous NUCLEI (i.e., groups of neuronal cell bodies or neuronal somata) that control specific aspects of ____________________.

homeostasis

Sensory (principally pain) and visceral integration are performed by the ________________ lobes.

insula (folded inside the brain)

Groups of neuronal cell bodies within the Hypothalamus are known as __________________.

nuclei

Conscious perception of vision is performed by the _________________ lobes.

occipital

Understanding speech and formulating words to express thoughts is performed by the _______________ lobes.

parietal