nervous system Flashcards
what is the nervous system responsible for?
1) much like a computer but far more complex; the nervous system CONTROLS and ADJUSTS the activites of other systems
what nervous system controls the brain and spinal cord?
the central nervous system
what is the Central Nervous System responsible for?
1) integrating, processsing and coordinating sensory input and motor output 2) intelligence, memory, learning and emotion all stem from the Central Nervous System
what does the peripheral nervous system include?
1) All the Neural tissue outside the CNS.
what is the main function of the peripheral Nervous System?
1) provides sensory information to the CNS and carries motor commands from the CNS to peripheral tissues and systems.
what are the 2 subdivisions within the peripheral nervous system and what are their function?
1) afferent division A) brings sensory information to CNS 2)Efferent division A) CARRIES motor commands to muscles and glands
what do receptors within the afferent division do?
1) monitor specific characteristics of environment 2) a receptor can be a dendrite, a specialized cell, cluster of cells, or a complex sense organ like the eye
where does the efferent division end?
1) at the EFFECTOR: which is a muscle cell, gland cell, or another cell specialized to perform very specific functions
what do the somatic and visceral sensory receptors within the afferent device do?
1) somatic sensory receptors A) monitor skeletal muscles, joints and skin 2) Visceral Sensory receptors- A)monitor internal structures like smooth muscle, cardiac muscle, glands and respiratory and digestive organs.
which division is responsible for delivering information to special sense organs, such as eye and ear
AFFERENT DIVISION
which division includes somatic nervous system and autonomic nervous system and what do they do?
1)Somatic Nervous system A) controls musclular contactions 2) Autonomic Nervous system A)regulates smooth muscle, cardiac muscle and glandular activity
the somatic nervous system activities may be
voluntary: muscle contractions are controlled voluntarily involuntary: outside your awareness. ex you touch something hot it will withdraw immediately.
what is a Neuron?
basic functional unit of nervous system. HIGHLY speicialized cell.
what is a sensory Neuron and what does it do ?
1) A neutron whose axon carries sensory information from PNS to CNS
what does a Motor Neuron do?
1) a neutron whose axon carries motor commands from CNS towards effectors
what is a neuroglia or glial cell ?
1)suppporting cells interact with neurons and regulate extracellular environment. 2) Defend Pathogens and perform repairs in neural tissue
Within Neural tissue there are two distinct cells; Neurons and Neuroglia. What is the function of a Neuron and Neuroglia?
1) A Neuron is what transmits and processes information in the nervous system 2)A Neuroglia or glial cell support the neurons. They A)act as phagocytes, B)provide a supportive framework and C)maintain the intercellular environment * around 100 billion glial cells. approximately 5 times the number of neurons
what is the function of a Soma in a neuron?
1) Cell body- contains nucleus, mitochondria,ribosomes and other organelles 2) biosynthesizes organic molecules such as enzymes
What is the function of Dendrites within a Neuron?
1) stimulated by environmental changes or actvities of other cells
what is the function of an Axon within a Neuron?
1) conducts nerve impulses ( action potential) towards synaptic terminals
What is the synaptic Terminal and what does it do?
1) It is where the neuron communicates with another cell
What are the 4 kinds of GLIAL or NEUROGLIA cells found within the central nervous system ?
1) Astrocytes 2)Oligodendrocytes 3) Microglia 4) Ependymal cells
What are the significant functions of the Astrocytes?
1) Controls Interstitial environment A)increase surface area of cell B)allows scavenging of ions, neurotransmitters or metabolic by-products that accumulate in microenvironment. C)This enables astrocytes to control chemical content of interstitial environment within CNS D) Therefore they isolate neurons from changes in chemical composition of interstitial space within CNS 2)Maintain blood brain barrier A)Neural tissue must be biochemically and physically isolated from general circulation because of hormones or chemicals in blood would be harmful to neuron function. B)Chemicals secreted by asctrocytes are CRUCIAL for the maintenance of blood-brain barrier 3)provides mechanical and structural strength. supports neurons of brain and spinal cord. 4) repair damaged sites within neural tissue. A) make structural repairs stabilize tissue prevent injury by producing scar tissue 5) Direct growth and interconnnection of developing neurons through secretion chemicals known as NEUROTROPIC FACTORS
what are the main functions of Oligodendrocytes?
* similar to astrocytes however have smaller cell bodies and less cytoplasmic processes 1) improve functional performance of Neurons by wrapping axons in MYELIN which INSULATES neurons 2)Internodes- large areas wrapped in myelin 3) Myelin sheath gaps- small gaps between myelin sheaths 4) white matter- regions in CNS dominated by myleninated axons 5)Gray areas- regions dominated by neuron cell bodies, dendrites and unmyelinated axons
What is the function of Microglia?
*smallest of glial cells 1) first appear in embryonic stem cells through division of mesodermal stem cells 2) Stem cells that create Microglia originate in bone marrow and are related to those that make macrophages and monocytes of blood. 3) migrate to CNS and are the police force. A) Phagocytic- engulfing cellular debris and waste products. B) protect CNS by phagocytosing viruses, microorganisms and tumor cells * only 5 percent of glial cells microglial. but multiply dramatically during infection or injury
What are the function of Ependymal Cells?
1) line ventricels of brain and central canal of spinal cord 2)filled with cerebrospinal fluid. this fluid provides a protective cushion and transports dissolved gases, nutrients, wastes and other materials. * cuboidal to columnar in shape 3) act as receptors that monitor composition of CSF 4) free surfaces of ependymal cells covered with cilia. ciliated ependymal cells assist circulation CSF. 5) specialized ependymal cells participate secretion of cerebrospinal fluid
what are the Neuroglia of the peripheral nervous system?
1) satellite cells 2) schwann cells
what are ganglia
cell bodies in PNS clustered together