Intro To Nervous. System Flashcards
Give an overview of the nervous system
Structural: CNS(brain & spinal cord) & PNS(all other nervous tissue)
Functional: PNS(somatic & visceral)
PNS
Somatic: voluntary control- sensation from the body wall and limbs to CNS and motor neurons back to skeletal muscle
Visceral: involuntary control-sensation from organs to CNS and motor neurons to cardiac muscle, smooth muscle and glands
What are the components of PNS?
-All neurons tissue outside of CNS that connects CNS to the body wall and organs
- Cranial nerves
- emerge from brain (12 pairs)
- Spinal nerves
- emerge from spinal cord (31 pairs)
- Ganglia
- consist of neuron cell bodies outside the brain a spinal cord
- enteric plexuses -help regulate digestive system
- sensory plexuses
What are the sensory functions of the nervous system?
- detect internal stimuli
- detect external stimuli
- carries information into the brain and spinal cord
What is the integrative function of the nervous system?
- processes sensory information
- analyzes and stores information
- makes decisions for appropriate responses
- perception: conscious awareness of sensory stimuli
What is the motor function of the nervous system?
- elicits an appropriate response
- activates effector muscles and glands leading to contraction and secretion
What are neuroglial cells?
Support cells
What are neurons?
The functional cells in the nervous system that contain typical cellular organelles within their cytoplasm
-respond to a stimulus and conducts the stimulus and conducts the stimulus along the length kf the cell (action potential)
What does the neuron cell body/ soma contain?
-contains the nucleus, and other typical cell organelles: cytoplasm, lysosomes, mitichondria, Golgi complex, free ribosomes, Nissan bodies (clusters of rER)
What is the neuron dendrite composed of?
- extend from cell body
- carries information towards the cell body
- branched
What does the axon composed of in the neuron?
- is a long, thin projection from the cell body
- carries information away from the cell body toward another neuron, muscle, or gland
- contains mitochondria, Microtubules, neurofibrils, does not contain rER)
- ends at synaptic end bulb (terminal bouton)
What is the classification of neurons by structure?
By number of processes extending from the cell body
Multipolar- have several dendrites and one axon
Pseudo polar(unipolar)- one continuous process (axon) that emerges from the cell and divides into two processes
Bipolar- have one main Dendrite and one axon
Classify neurons by function
Motor-efferent
- Conveys impulses to effector cells
- Somatic-skeletal muscles
- Visceral- smooth cardiac muscles, glands found in organs
- Typically multipolar
Sensory- Afferent
- Conveys impulses from receptors for integration
- Somatic - pain, temp, touch, pressure, proprioception
- Visceral- distension, ischemia, inflammation, physiological processes from internal organs, glands, blood vessels
- Typically pseudounipolar or bipolar
Interneuron (integrative)
-Communication and integration between sensory and motor neurons, tendon reflexes
What are neuroglial cells?
- make up about half the volume of CNS
- generally smaller than neurons
- do not generate action potentials
- are able to multiply and divide if injured
Where are each type of neuroglial cell found?
CNS
- astrocytes
- oligodendrocytes
- microglia
- ependymal cells
PNS
- Schwann cells
- satellite cells
What are the components of the CNS?
- white matter is composed of myelinated tracts of axons
- Grey matter is composed of neuronal cell bodies
- Collection of cell bodies is called a nucleus
- Collection of axons is called a tract
What are the components of the PNS?
- Collection of cell bodies is called a ganglion
- Collection of axons is called a peripheral nerve
What is the function of the central hemisphere?
- Surface area of the brain is larger than the space in the cranial cavity which causes folding
- folds= gyri are separated by grooves = sulci
- Deep groove called longitudinal fissure- separates left and right cerebral hemispheres
- Special sulci separates lobes
- Generalized functions of loves
- sensory, motor, visual, auditory, language and higher cognitive functions, memory etc.
Wast is the function of the thalamus?
- relaying and modulating sensory input to cerebrum
- modulating cerebral activity to regulate motor function
What is the function of the hypothalamus?
Homeostasis; growth and reproduction
What is the function of the brain stem?
- Midbrain, Pons and Medulla Oblangata
- Vegetative functions such as cardio regulation, swallowing, yawning etc.
What is the function of the cerebellum ?
Posture, balance and smooth coordinated movements
Summarize PNS
-Axons of neurons forming peripheral nerves exiting the cerebral cortex and brain stem
12 pairs
- Cortex = CN 1- CN 2
- Midbrain = CN 3-4
- Pons= CN 5-8
- Medulla= CN 9-12
Can consist of motor, sensory, parasympathetic fibers
Suummar8ze the internal organization of the spinal c9rd
Made up of two types of tissue:
- inner gray matter (nuclei)- cell bodies of neurons and glial cells
- outer white matter (tracts)- myelinated axons, neural “highways”
Segments
-cervical, thoracic, lumbar, sacral and coccygeal
What are the PNS spinal nerves?
-Axons of neurons forming peripheral nerves exiting the spinal cord segments
- 31 pairs
- 8 cervical (C1-C8)
- 12 thoracic (T1-T12)
- 5 lumbar (L1-L5)
- 1 coccygeal (Co1)
Can consist of motor, sensory, sympathetic and parasympathetic fibers
Summarize the spinal cord and spinal nerve organization
- Somatic afferent: from skin, fascia, of the body wall specifically the back
- Somatic afferent: from skin, fascia of the b9dy wall the rest of the body
- Somat8c efferent: to the skeletal muscle of the deep of the back
Somatic efferent: skeketal musc”s ti the rest of the body
Summarize formation of the typical spinal nerve
- Dorsal horn (sensory)—> dorsal rootlets (sensory )—> dorsal roots—> spinal nerve (mixed)—> dorsal Ramus (mixed) or ventral Ramus
- Ventral (motor) —>. Ventral rootlets(motor )—> ventral root(motor)—> spinal nerve (mixed) —> dorsal Ramus (mixed) or ventral Ramus
