functions of spinal cord
integrates and processes information on its own, in addition to relaying information to and from the brain
expanded regions with increased gray matter to provide innervation of the pectoral girdle and upper limbs
expanded region of the spinal cord with increased gray matter to provide innervation of the pelvic girdle and lower limbs
where the spinal cord tapers to a conical tip, which is at or inferior to the level of the first lumbar vertebrae (L1)
a strand of fibrous tissue, originating at the conus medullaris and extending through the vertebral canal to the second sacral vertebra, ultimately becoming part of the coccygeal ligament
dorsal root ganglia
contains sensory neuron cell bodies, each segment of the spinal cord is associated with a pair of these
contains the axons of the sensory neurons in the dorsal root ganglion; each segment of the spinal cord is associated with a pair of these
contains axons of somatic motor neurons and sometimes visceral motor neurons that control peripheral effectors; each segment of the spinal cord is associated with a pair of these
location where sensory and motor fibers unite, emerging from intervertebral foramina; distal to each dorsal root ganglion. is considered a mixed nerve
inferior extension of the ventral and dorsal roots and the filum terminale in the vertebral canal
a series of specialized membranes that provide physical stability and shock absorption for neural tissues of the spinal cord
tough, fibrous outermost layer of the spinal cord; caudally it forms the coccygeal ligament with the filum terminale
formed where the spinal dura mater tapers from a sheath to a dense cord of collagen fibers that ultimately blend with components of filum terminale
internal to the inner surface of the dura mater; separates the dura from the arachnoid mater
• Lateral extensions of pia mater that pass through the arachnoid layer and attach to the internal surface of the dura mater • Function to anchor the spinal cord
central gray matter
surrounds the central canal in the spinal cord and contains cell bodies of neurons and glial cells
peripherally situated; contains large numbers of myelinated and unmyelinated axons organized into tracts and columns
posterior and anterior to the lateral canal; contain axons of interneurons that cross from one side of the cord to the other
outermost layer of connective tissue on the spinal nerve; a dense network of collagen fibers
middle layer of connective tissue on the spinal nerve; partions the nerve into a series of bundles (fascicles) and conveys blood vessels into each individual fiber
inner layer of connective tissue on the spinal nerve; composed of delicate connective tissue fibers that surround individual axons
first branch of spinal nerve in the thoracic and upper lumber region; contains myelinated axons going to an autonomic ganglion
exits the autonomic ganglion, carries axons that innervate glands and smooth muscles in the body wall or limbs back to the spinal nerve
consists of the ventral rami of C1-C4 and some fibers from C5; innervates the muscles of the neck, thoracic cavity and diaphragm
consists of ventral rami C5-T1; innervates the pectoral girdle and upper limbs; nerves in this plexus originate from cords or trunks
contains fibers from spinal segments T12-L4; originates from the posterior abdominal wall and ventral rami of nerves supplying the pelvic girdle and lower limbs
contains fibers from spinal segments L4-S4; originates from the posterior abdominal wall and ventral rami of nerves supplying the pelvic girdle and lower limbs
specialized cell that monitors conditions in the body or external environment; has a characteristic range of sensitivity
reflex in which important interconnections and processing occur inside the spinal cord; range from monosynaptic to polysynaptic
The region at the center of an A band of a sarcomere that is made up of myosin only and gets shorter during muscle contraction.
motor end plate
The portion of the cell membrane at the neuromusclar junction; essentially the postsynaptic membrane at the synapse.
synaptic gap or synaptic space; tiny gap between the terminal of one neuron and the dendrites of another neuron (almost never touch); location of the transfer of an impulse from one neuron to the next
vesicles dump this so that the axon terminal has a way to communicate with the motor end plate.
this carries information from the brain to the muscles; also called "efferent"
enlarged areas of the sarcoplasmic reticulum surrounding the transverse tubules, which store calcium for release at the start of muscle contraction
sodium potassium pump
A special transport protein in the plasma membrane of animal cells that transports sodium out of the cell and potassium into the cell against their concentration gradients.
Active transport protein; pumps calcium ions across a cell membrane against their concentration gradient.
A helical protein that winds around actin helices in skeletal and cardiac muscle cells to form the thin filament of the sarcomere.
The connection of a myosin head group to an actin filament during muscle contraction (the sliding filament theory).
The step in the sliding filament theory during which myosin undergoes a conformational change to its low energy state, in the process dragging the thin filaments (and the attached Z lines) toward the center fo the sarcomere.
release/reactivate energy in myosin and active transport for calcium into terminal cisternae
ATP is used to what during muscle contractions?
begins at stimulation and typically lasts 2msec and continues until calcium is released from the terminal cisternae
begins as Calcium bind to troponin and myosin "cross bridge" bind to actin and power strokes are occurring; lasts about 15msec
Calcium is being actively transported back into the terminal cisternae causing calcium levels to fall, active sites on Actin are being re-covered by tropomyosin, and tension falls to resting levels: lasts about 25msec
repeated stimulation after relaxation phase has completed in a muscle. Can occur over the next 30-50 stimulations.
multiple motor unit summation
The strength of a muscle contration is determinded not only by the frequency of stimulation, but also by the number and size of motor units recruited, The number of motor units that are recruited is determined by the number of motor neurons that are stimulated by the central nervous system
______is repeated stimulation of the muscle so that the muscle is never allowed to completely relax. will yield increased tension is produced
if stimulation frequency is high enough, muscles never BEGIN to relax and is continuous contraction
involving muscular contraction in which tension increases and the muscle length changes
A substance, stored in the muscles, that helps supply energy for muscle contraction and can be taken as a supplement or created by your own body. this is a way to store ATP in the muscle.
white fibers; large in diameter, contain densely packed myofibrils and large glycogen reserves and relatively few mitochondria
red fibers; half the diameter of fast fibers and take about 3x as long to contract after stimulation; surrounded by extensive capillaries; therefore higher supply of oxygen; contain myoglobin (reserve of oxygen)
"All or none principle"
applies to muscle fibers and motor units either it contracts or it doesn't, Either the action potential occurs or it doesn't, this is called the?
Abundant star shaped cells found throughout the CNS, cleaning up debris in the extracellular space and removing neurotransmitters from the synaptic cleft, connects neurons to nearby cappilaries, components of the blood-brain barrier
Spider-like phagocytes; dispose of debris, smallest neuroglial cells; phagocytic cells that enculf cellular debris, waste products and pathogens. increase in number as a result of infection or injury
Supporting cells of the peripheral nervous system responsible for the formation of myelin. Wrap around one neuron at a time
intermediate cytoskeleton that maintains cell shape, bundles of intermediate filaments (neurofilaments); maintain shape
Found in neural pathways in the central nervous system; connect sensory and motor neurons
smooth muscle regulation, heart and blood pressure regulation, regulation of glands, digestive system regulation
Similar to blood plasma composition, formed by the choroids plexus, forms a watery cushion to protect the brain, circulated in the arachnoid space, ventricles, and central canal of the spinal cord
Cerebrovascular Accident (CVA)
commonly called a stroke, the result of a ruptured blood vessel supplying a region of the brain
Autonomic Nervous System
The involuntary branch of the nervous system (divided into Sympathetic and Parasympathetic divisions), the part of the nervous system of vertebrates that controls involuntary actions of the smooth muscles and heart and glands
norepinephrine and epinephrine neurotransmitters, Fight-or-Flight, response to unusual stimulus (E's exercise, excitement, emergency, and embarrassment)
(housekeeping activities) conserves energy, maintains daily nevessary body functions (D's digestion, defecation, and diuresis)