Histology Final Chapter 10 Nervous System

Nervous system

What is the most complex system in the human body and has billions of neurons?

Billions of neurons that are assisted by many more supporting cells called glial cells

What is the nervous system formed by?

Glial Cells

Supporting cells that aid nerve cells, that have short processes, support and protect neurons.

Neurons and glial cells

Two kinds of the nerve tissue in the CNS AND PNS

Neurons

what helps complete Numerous long processes in the nervous system?

Many neural activities, neural nutrition, and defense of cells in the CNS

What do glial cells participate in?

CNS and PNS

The two major divisions in the Nervous system?

Brain and Spinal Cord

What does the CNS consist of?

Composed of the cranial, spinal, and peripheral nerves conducting impulses to and from the CNS (sensory and motor nerves, respectively) and ganglia that are small aggregates of nerve cells outside the CNS

What does the PNS consist of?

Third week of development

When does the nervous system develop?

Outermost of the three early embryonic layers (The ectoderm)

Where does the nervous system develop?

Somatic and Visceral

What are the two subdivisions of the Sensory division (afferent)?

Somatic and Autonomic

What are the two subdivisions of the Motor division (efferent)?

Sensory input perceived consciously ex: eyes, ears, and skeletal structures

What is the somatic sensory?

Sensory input not perceived consciously or voluntarily Ex: internal organs and cardiovascular structures

What is the Visceral sensory?

Motor output controlled consciously or voluntarily Ex skeletal muscle effectors

What is the somatic motor?

Motor output not controlled consciously ex Heart or gland effectors

What is the autonomic motor?

Preganglionic and Postganglionic neurons

What are the two neurons in the ANS?

In the CNS

Where is the cell body of the preganglionic?

In the ganglion

Where is the cell body of the postganglionic neuron?

Parasympathetic and Sympathetic Division

What are the two division of the ANS?

Maintains normal body homeostasis

What is the function of the parasympathetic sub division?

Within or near the effector organs

where does the ganglia occur of the parasympathetic division?

Controls the bodys responses during emergencies and excitement (fight of flight)

What is the function of the sympathetic division?

near the CNS

Where does the ganglia occur in the sympathetic division?

ANS components that are located in the wall of the digestive tract

What is the Enteric Nervous system?

Cell body, Dentrites and Axon

What are the three parts of a Neuron?

The cell body

What contains the nucleus and most of the cells organelles and serves as the synthetic and trophic center?

Dentrites

What are numerous elongated processes extending form the perikaryon and specialised to receive stimuli at synapses?

Snynapses

Unique sites on the dendrite that receive stimuli

Axon

what are a single long processes ending at synapses specialised to generate and conduct nerve impulses to other cells ex nerve, muscle and gland cells?

Unipolar, bipolar, multipolar, and anaxonic

What are the types of neurons?

One axon and two or more dendrites. also the most common in the body

what are multipolar neurons?

one dendrite and one axon

what are bipolar neurons?

Retina, olfactory epithelium and the inner ear

where are bipolar neurons found?

includes all sensory neurons. Single process that bifurcates close to the perikaryon, with longer branch extending to a peripheral ending and other towards the CNS

What are the unipolar/pseudounipolar neurons?

Many dendrites but no true axon, do not produce action potentials, but regulate electrical changes of adjacent CNS neurons

What are the Anaxonic Neurons?

Afferent, receiving stimuli from receptors throughout the body

What are sensory neurons?

Efferent, Sending impulses to effector organs such as muscle fibers and glands

What are motor neurons?

Grey Matter

Where do the CNS cell bodies of the neuronal cells concentrated?

White Matter

Where are CNS axons of neuronal cells concentrated?

Ganglia nd in some sensory regions. such as te olfactory mucosa

Where are the PNS cell bodies found?

They are bundled in nerves

where are the axons of the PNS cells found?

Slowly progressing disorder affecting muscular activity characterized by tremors, reduced activity of the facial muscles, lose of balance and postural stiffness

What is Parkinson’s disease?

the gradual loss by apoptosis of dopamine producing neurons whose cell bodies lie within the nuclei of the CNS substantia nigra

What is the cause of parkinsons disease?

L-dopa. which is a precursor of dopamine that augments the declining production of this neurotransmitter

how is parkinsons disease treated?”

10 times

Glial cells are ___________ more abundant than neurons in the mamalian brain

Micro environments that are optimal for neuronal activity

What do glial cells help create?

Connective tissue

What do glial cells substitute?

Two

How many glial cell are located in the PNS?

Four

How many glial cells are located in the CNS?

common type of dementia in the elderly, affects both neuronal perikarya and synapses within the cerebrum

What is Alzheimer disease?

Due to neurofibrillary tangles, which are accumulations of tau protein associated with microtubules of the neuronal perikaryon and axon hillock regions ans neuritic plaques

What causes the functional defects of alzheimer disease?

Which are dense aggregates of Beta-amyloid protein that form around the outside of these neuronal regions

what are neuritic plaque?

Lack of collagen

What makes the CNS relatively soft and easily damaged during injury?

Lipid rich myelin

What causes the difference in areas of white and grey matter in the CNS?

tracts of myelinated axons and myelin producing oligodendrocytes

what are the main components of white matter?

Cell bodies, dendrites, astrocytes, microglial cells, and most synapses

what are the main components of the grey matter?

Thick cortex or surface layer of both the cerebrum and cerebellum

What does the grey matter make up?

Peripheral

where is the white matter located in the spinal cord?

Deeper, H shaped Mass

what does the grey matter of the spinal cord form?

Anterior Horns

The two anterior projections of the grey matter in the spinal cord are called?

Cell bodies of very large motor neurons whose axons make up the ventral roots of spinal nerves

What do the anterior horns contain?

Interneurons which receive sensory fibers from neurons in the spinal (dorsal root) ganglia

what do the posterior horns contain?

The lumen of the neural tube, is continuous with the ventricles of the brain

Where does the central canal develop?

Ependymal cells and contains CSF

What lines the central canal?

membranes of connective tissue between the bone and nervous tissue

What are meninges?

Neural Tube

What is the origin of Oligodendrocyte, Astrocyte, and Ependymal Cells?

Bone marrow (monocytes)

What is the origin of the Microglia?

Neural Crest

What is the origin of Schwann and Satellite Cells (of ganglia)?

CNS

What is the Location of the Oligodendrocyte, Astrocyte, and Microgila?

Line ventricles and central canal of CNS

What is the location of the Ependymal cells?

Peripheral Nerves

What is the location of the Schwann Cells?

Peripheral ganglia

What is the location of the Satellite cells (of ganglia)?

Myelin prodcution, electrical insulation

What is the main function of the Oligodendrocyte and Schwann cell?

Structural and metabolic support of neurons, especially at synapses; repair processes

What is the main function of the Astrocyte?

Aid production and movement of CSF

What is the main function of Ependymal cells?

Defense and immune-related activities

What is the main function of Microgila?

Structural and metabolic support for neuronal cell bodies

What is the main function of Satellite cells?

Dura, Arachnoid, and pia maters

what are the three types of meninges?

Dense irregular connective tissue organiuzed as an outer peristeal layer continuous with the periosteum of the skull and an inner meningeal layer

What does the dura mater consist of?

Along the superior sagittal surface and other specific areas around the brain.

Where do the outer periosteal and inner meningeal separate?

Blood filled dural venous sinuses

What forms when the outer periosteal layer and inner meningeal layer spearate?

Thin Subdural space

How is the dura mater separated from the arachnoid?

A sheet of connective tissue in contact with the dura mater. a system of loosely arranged trabeculae composed of collagen and fibroblasts, continuous with the underlying pia mater layer

What are the two components of arachnoid?

Subarachnoid space

What is a sponge like cavity with CSF?

Ventricles of the brain

Where is CSF produced?

Arachnoid Villi

What are CSF-filled protusions that absorb CSF into the blood of the venous sinuses?

Flattened Mesenchymally derived cells closely applied to the entire surface of the CNS

What does the pia mater consist of?

Very thin superficial layers of astrocytic processes that separate the pia from nerve cells

What is the Glial limiting membrane or glia limitans?

Pia mater and the layer of astrocytic end feet

What forms a physical barrier separating CNS tissue from CSF?

Blood vessels from the arachnoid

Where does brain tissue get its oxygen and nutrients?

a functional barrier that allows much tighter control than that in most tissues over the passage of substances moving from blood into the CNS tissue

What is the blood brain barrier (BBB)?

Capillary Endothelium

What is the main structural component of BBB?

Cells are tightly selaed together with well-developed occulding junctions, with little to no transcytosis

What makes the Endothelium such an important aspect to the BBB?

Limiting layer of perivascular astrocytic feet

What further regulates passage of molecules and ions from blood to brain?

bacterial toxins, infectious agents, and other exogenous substances

What does the BBB protect neurons and glia from?

maintain the stable composition and constant balance of ions

How does the BBB help interstitial fluid?

Regions of the hypothalamus where plasma components are monitored, in posterior pituitary, or choroid plexus

Where is the BBB NOT present?

Highly vascular tissue , elaborately folded and projecting into the large ventricles of the brain

What does the choroid plexus consist of?