A&P Nervous System

What are the major functions of the nervous system?

1) maintenance of body homeostasis by regulation and coordination of all organ systems.
2) Acts as the sensor and control center for many systems
3) provides communication between the control center sensors and effectors.

What three parts make up the simple reflex arc?

Sensory function. (nerve receptor)
Integrative function. (CNS)
Motor function. (effector)

How do the three parts of the simple reflex arc is related to a homeostatic control system.

The system becomes out of balance.
The sensory receptor (nerve) relays information about the system to the integrator (CNS). The integrator sends a signal to an effector to recreate balance. The effector acts upon the system. The sensor continues to send information about the system to the integrator, continuing the cycle.

What are the three major parts of a nerve?

Cell body, Dendrites and Axon.

What are the functions of the dendrites?

Conduct signals toward cell body.

What are the functions of the Axon?

Conduct signals away from the cell body.

What are the functions of the Cell body of a nerve?

Nutritional center.

Describe the general structure of a nerve:

Tentacle dendrites (receptors) attached to a cell body (center) with a long tail, (Axon, sender).

What cells are in the nervous system?

1) Neurons,( function to act as receptors, conduct electrical impulses, and release chemical messengers, do not divide but have the ability to repair.)
2) Neuroglial cells: function in mechanical and metabolic support of neurons.

What are the two ways to classify neurons?

Functional and Structural.

What are the structural classifications of neurons?

1) Multipolar neurons
2) Bipolar neurons
3) Unipolar neurons

What are the functional classifications of neurons?

1) Sensory or afferent neurons
2) Motor neurons
3) Interneurons or association neurons

Describe the form of multipolar neurons:

Three or more processes, one axon and the rest dendrites. (Multi processes or multi tenticles.) ( Most common neuron in humans, 99% major type of CNS)

Describe the form of Bipolar neurons:

Two processes, 1 dendrite and 1 axon extending from opposite sides of the cell. (Rare sensory nerves, retnia and olfactory)

Describe the form of Unipolar neurons:

Pseudo bipolar neurons. Short process with two long branches which are one Axon. Or, a nuclear body attached to the side of a long Axon (Chiefly found in ganglia in PNS)

Describe the function of Sensory (or afferent) neurons

Transmit impulses from the sensory receptors in the skin or internal organs to the CNS.

Describe the function of Motor neurons

Cary signals away from the CNS to effector organs (muscles and glands)

Describe the function of Interneurons (or associated neurons)

Lie between motor and sensory pathways and shuttle signals through the CNS pathways where integration occurs. (Most interneurons are confined within the CNS)

What are the five types of neuroglial cells.

Astrocytes, Microglia, Ependyma, oligodendrocytes, schwann cells (neurolemmocytes)

describe astrocytes cells:

In CNS, Provide metabolic and structural support for neurons.

What neuroglial cells would help regulate exchange between blood and neurons?

Astrocytes.

describe microglia cells:

In CNS, and act to protect neurons from pathogens and may be phagocytic.

What neuroglial cells would help protect the neurons from a foreign pathogen?

Microglial cells.

Describe ependyma cells.

In CNS, Line the cavities in the brain ans spinal cord and form a selective barrier between blood and cerebrospinal fluid.

Describe oligodendrocytes:

In CNS,Wrap around axons to provide an insulating myelin layer that increases the efficiency of conduction of neural signals.

Describe Schwan cells:

In PNS, wrap around axons of neurons to form a myelin sheath that helps speed up the conduction rate of neural signals.

Line the cavities in the brain ans spinal cord and form a selective barrier between blood and cerebrospinal fluid.

Describe ependyma cells.

What cells help with more efficient transmission of signals.

Oligodendrocytes and Schwann cells.

What are the similarities and differences of Oligodendrocytes and Schwann cells.

Both help speed up transmission of signals, Schwann cells are in PNS while Oligodendrocytes are in CNS. Schwann cells attach to only one Axon where Oligodendrocytes attach to many Axons.

What are the major divisions of the nervous system?

Brain and Spinal cord.

What are the coverings of the brain?

There are many layers covering the brain. The most exterior is the scalp. The Periosteum of the cranium and bone of the skull are next. There are three Meninges.

What are the three meninges or layers of connective tissue covering the brain?

Dura Matter, Arachnoid Matter, Pia Matter.

What is the form of the the Dura Matter

Tough Mother. Strongest menix. Two layers: periosteal and meningeal. Periosteal connects to the skull. The meningeal layer is the true external covering of the brain. Also extend inward to subdivide the cranial cavity.

What is a menix?

Layer of connective tissue for protection. Also known as Matter. Plural Meninges.

What is the function of the Dura Matter

Protect the brain from outside invasion and limit movement of the brain.

What is the form of Arachnoid matter?

Middle menix. Forms a loose brain covering, never dipping into the sulchi. Separated from the Dura Matter by a narrow serous cavity, the subdural space, which contains a film of fluid. Weblike extensions span this space and secure the arachnoid matter to the underlying Pia Matter.

What is the function of the Arachnoid matter?

Provide a layer of cerebral spinal fluid protecting the brain from shock. Nurturing the brain through CNS and blood vessels.

What is the form of Pia Matter?

Gentle Mother. Delicate connective tissue and richly invested with tiny blood vessels. Clings tightly to the brain.

What is the function of Pia Matter?

Protect the brain. Barrier between CNS and Brain. Nourish the brain through its many vessels.

What is the function of CSF?

Nourishing: Provides vital nutrients.
Protection: from from blows and trauma.
Structural Support: Forms a liquid cushion that gives buyoncy to the Brain and CNS. Floating the brain reduces the weight of the brain by 97% and keeps the brain from crushing under its own weight.

Where is CSF formed?

In Choroid Plexus that hang from the roof of each ventrical.

How is CSF Formed?

Ependymall cells filter blood to create and cleanse CSF

What is the blood brain barrier?

Protective mechanism that helps maintain a stable environment for the brain.

What is the MAJOR function of the blood brain barrier.

Protect the brain from the chemical zoo of the blood. If the many chemicals of the blood acted upon the brain, the nerves of the brain would fire uncontrollably.

How are simple squamous cells organized in the blood brain barrier?

Very tightly connected with tight junctions in order to separate blood and CSF.

What are the major parts of the brain?

1) Cerebrum. (cerebral hemispheres)
2) Diencephalon
3) Brain Stem
4) Cerebellum

What are the three parts of the Cerebral Hemisphere?

Cortical grey matter, White matter and Basal Nuclei (ganglia).

What are the functions of the cortical grey matter in the Cerebrum?

Localizes and interprets sensoryinputs, controls voluntary and skilled skeletal muscle activity and functions in intellectual and emotional processing.

What are the functions of White matter in the cerebrum?

Communication between the cerebral areas and between the cerebral cortex and lower CNS centers.

What are the functions of the Basal Nuclei in the Cerebrum?

Subcortical motor centers important in initiation of skeletal muscle movement. Deep within white matter.

What are the two parts of the Diencephalon?

Thalamic nuclei (Thalmus) and Hypothalamus.

What are the functions of the Thalamic nuclei in the Diencephalon?

Relay stations of (1) sensory impulses to derebral cortex for interpretation and (2) impulses to and from cerebral motor cortex and lower (subcortical) motor centers, including cerebellum. The thalamus is also involed in memory and emotional processing. (The Gateway to the cerebral cortex!)

What are the functions of the Hypothalamus nuclei in the Diencephalon?

Chief integration center of autonomic (involuntary) nervous system. Regulates body temperature, food intake, water balance, thirst, biological rhythms and drives. Regulates hormonal output of anterior pituitary gland and is an endocrine organ in its own right. Part of limbic system.

What are the three parts of the Brain Stem?

Midbrain, Pons and Medulla oblongata.

What are the functions of the Midbrain in the Brain Stem?

Conduction pathway between higher and lower brain centers (cerebral peducles contain the fibers of the pyramidal tracts) Its superior and inferior colliculi are visual and auditory reflex centers. Substantia nigra and red nuclei are subcortical motor centers. Contains nuclei for cranial nervs III and IV.

What are the functions of the Pons in the Brain Stem?

Conduction pathway (bridge) between higher and lower brain centers, pontine nuclei relay information from the cerebrum to the cerebellum. Respiratory nuclei cooperate with the medullary respiratory centers to control respiratory rate and depth. House nuclei of cranial nervs V-VII

What are the functions of the Medulla Oblongatta in the Brain Stem?

Conduction pathway between higher brain centers and spinal cord, and site of decussation of the pyramidal tracts. Houses nuclei of cranial nervs VII and XII. Contains nuclei cuneatus and gracilis (synapse points of ascending sensory pathways transmitting sensory impulses from the skin and propriceptors) Contains visceral nuclei controlling heart rate, blood vessel diameter, respiratory rate, vomiting, coughing etc... Olivary nmuclei provide sensory relay to the cerebellum.

What are the functions of the Cerebellum?

Processes information from cerebral motor cortex and from porprieceptoers and visual equilibrium pathways. Provides instructions to cerebral motor cortex and subcortical motor centers that result in proper balance and posture with smooth coordinated skeletal muscle movements.

What is the fissure that separates the left and right hemispheres of the brain?

The longitudal fissure

What is the sulcus that seperates the sensory and motor areas of the brain?

Central Sulcus

Location of primary motor cortex?

Anterior to the central sulcus on the precentral gyrus.

Location of Primary somasensory cortex.

Dorsal to the central sulcus on the post central gyrus.

Location of the premotor cortex?

Anterior to the motor cortex on the frontal lobe.

What separates the frontal and parietal lobes?

Central Sulcus.

Function of primary (somatic) motor cortex?

consciously control the the precise or skilled voluntary movements of skeletal muscles.

Function of Primary somasensory cortex?

Neurons receive information from the general sensory receptors in skeletal muscles, joints and tendons. (propriceptors) and Spatial discrimination.

Location of the somasensory association cortex?

Dorsal to the primary somasensory cortex and expands over the parietal and occipital lobes.

Function of the somasensory Association cortex?

integrate sensory inputs in order to understand the object being felt. (size, weight, texture, relationship of parts etc...)

Function of Premotor cortex?

Controls learned motor skills of repetitive patterns. (playing musical instruments or typing) by coordinating muscle groups. (memory bank for skilled motor activities)

Location of Prefrontal cortex?

The anterior frontal lobe of the brain. (Most forward)

Function of Prefrontal cortex?

Personality, intellect and complex learning. Conscious thinking.

Location of General interpretation area?

Located in parts of temporal, parietal and occipital lobes.

Function of General interpretation area?

Involved in complex interpretation of all sensory input.

Location and function of visual cortex?

Occipital lobe, processes visual information.

Location and function of auditory cortex?

Temporal lobe, processes auditory information.

Location and function of olfactory cortex?

Temporal lobe. Processes olfactory information.

Location and function of gustatory cortex?

Parietal lobe. Processes gustatory information.

What does the right hemisphere of the cerebrum specialize in?

Visual spatial abilities, (Creative ability)

What does the left hemisphere of the cerebrum specialize in?

Language and analytic abilities.

Importance of corpus callosum?

Communicate between hemispheres, help integrate visual spatial with language and analytic abilities.

Describe lateralization and specialization of the brain:

In the effort to distinguish what parts of the brain have what functions, we try to place the action in the left or right hemisphere (laterization) and find the exact location in the brain of the function (specialization or dominance). But the reality is often much different than the specific locations that have been generally discovered. Left-handedness dramatically changes the normal patterns and so does birth defects.

what is the general function of the limbic system?

The emotional or affective (feeling) brain. Emotional response.

Describe the general structure of the limbic system:

Groups of cell bodies and fiber tracts that form a ring around the brain stem, including parts of the thalamus and hypothalamus. Also includes fornix mammillary body, and Olfactory bulb.

The olfactory bulbs play an important part of what brain system?

limbic system.

Is the limbic system connected to lower and higher regions of the brain?

Yes. These connections allow the limbic system to integrate and respond to a large variety of complex environmental stimuli.

What are the general functions of the Reticular Formation?

Receives sensory input. Maintains alert wakefulness of cerebral activity and helps filter out unwanted information. Focus senses and alertness.

Describe the general form of the Reticular Formation:

Complex network of nuclei and nerve fibers within the medulla, pons, midbrain, thalamus and hypothalamus.

Two General functions of the Spinal Cord?

Conducts nerve impulses to and from the brain.
Integrating center for spinal reflexes.

Location of Spinal cord?

Begins at foramen magnum, continuous with the brain stem. Extends down through the spinal column until it reaches the Conus Medullaris at L1 and L2.

What are the meninges of the spinal cord?

1) Dura Matter
2) Arachnoid Matter
3) Pia Matter

What are the two spaces of the Spinal cord?

Epidural Space, between duramatter and bone
Subarachnoid space. Between arachnoid matter and pia matter.

Form of Epidural Space:

Most outer space contains soft padding of fat cells and blood vessels.

Function of Epidural Space?

Protect and nourish Spinal cord.

Form of Subarachnoid Space?

Filled with CSF.

Function of Subarachnoid Space?

Blood barrier, Seperate Spinal cord from blood.

Function of Posterior Grey matter in Spinal cord:

Dorsal horns contain synapses between sensory organs and interneurons.

Function of Anterior Grey matter in Spinal cord:

Anterior, ventral horns contain motor neurons that control skeletal muscles.

Function of lateral Grey matter in Spinal cord:

Lateral horns contain motor neurons that control visceral effectors.

Function of white matter in spinal cord:

Nerve tracts, relay information between brain, Spinal cord and PNS.

Location of Dorsal tracts on Spinal Cord

Between dorsal horns.