Nervous Tissue, The spinal cord and Spinal Nerves, and The brain and cranial nerves
What are leakage gated channels?
Channels that randomly open and close. Has more k+ permeability than Na+. The passing of K+ and Na+ across the membrane maintains the resting membrane potential of -70 millivolts.
What are Mechanically gated channels?
Opens or closes in response to mechanical stimulation (touch, pressure, stretching, and vibration)
What are Voltage gated channels
Opens and closes in the response to change in membrane potential used to generate and conduct action potentials
What are Ligand gated channels?
Opens in the response to the binding of a ligand (chemical stimulus)
What is Saltatory Conduction?
Impulse along the exposed portions of myelinated axon appearing to jump or leap (fast) from node to node.
What are somas?
Cell body; Contains a nucleus surrounded by cytoplasm that includes typical cellular organelles.
What are axon terminals?
The axon and its collaterals end by dividing into many fine process. (telodendria)
What are three types of Structural Neurons?
Multipolar, Bipolar, and Unipolar
What are three types of functional Neurons?
Integrative (association or interneurons)
What neuron has several dendrites and one axon?
What neuron has one dendrite and one axon?
What neuron has one process that exits cell body but splits into axon and dendrite?
What neuron relays stimuli to brain or spinal cord?
What neuron analyzes and makes decisions regarding appropriate responses?
Integrative (Association or interneurons)
What neuron relays decisions to muscles or glands to react?
What are the divisions of the PNS?
SNS (Somatic nervous system)
ANS (autonomic nervous system)
ENS (Enteric nervous system)
Cranial nerves: 12
Soinal nerves: 31
Which nervous system controls voluntary neurons through use of efferent nuerons?
Somatic Nervous System (skeletal muscle, walking and smiling)
Which nervous system controls involuntary neurons?
Auntonomic nervous system (smooth muscle,cardiac muscles, and glands)
Which nervous system controls involuntary neurons in GI tract?
Enteric nervous system
What are effectors?
What responds to the motor neuron impulse. (Muscle and glands)
What are the four types of Neuroglia Cells in the CNS?
What are the two types of neuroglia cells in the PNS?
Describe an astrocyte cell.
They are the largest and most numerous of neuroglia. (Protoplasm)
The functions of the astrocytes is homeostasis, helps form blood brain barrier, nurse made to neuron, and neurotransmitter.
What produces myelin sheath in the CNS?
Which cell phagotycize microbes in nerve tissues?
Which cell forms blood cerebrospinal fluid barrier and makes and produce CSF?
What cell produces myelin sheath in the PNS?
What are the support neurons in the PNS ganglia?
What are myelin Sheaths?
A multi-layered lipid and protein covering around some axons that insulates them and increases the speed of nerve impulse conduction
What are nodes of ranvier?
gaps in the myelin sheath that appear at intervals along the axons.
Describe the development of Schwann cells.
Schwann cells begin to form myelin sheaths around axons during fetal development. Ech schwann cell wraps about 1mm of a single axons length by spiraling many times around the axon.
What are the parts of a Schwann cell?
Nucleus, cytoplasm, axon, neurolemma.
What are diverging circuits?
The nerve impulse from a single presynaptic neuron causes the stimulation of increasing number of cells along the circuit. (1 to many)
What are converging circuits?
several postsynaptic neuron receives nerve impulses from several different sources.
What are reverberating circuits?
The incoming impulse stimulates the first neuron, which stimulates the second, which stimulates the third, and so on. (breathing)
What does Parallel after-discharge circuit do?
stimulates a group of neurons/synapses with a common post synaptic cell. (Cortex of brain for higher learning)
What are spinal meninges?
Surrounds the spinal cord and are continuous with the cranial meninges. (spinal Column)
What are denticulate ligaments?
Triangular-shaped membranous extensions of the pia mater suspend the spinal cord in the middle of its dural sheath. (Thickenings of the pia mater)
What are the parts of the Reflex Arch?
1. Sensory receptor
2. Sensory neuron
3. Integrating center
4. Motor Neuron
What does Sensory receptors(1) do in a Reflex Arch?
Respnds to a stimulus by producing a generator or receptor potential.
What does sensory neurons (2) do in a Reflex Arch?
axon conducts impulses from receptor to integrating center.
What is the integrating center(3) in the reflex arch?
One or more regions within the CNS that relay impulses from sensory to motor neurons.
What happens in the motor neuron (4) in the Reflex Arch?
axon conducts impulses from integrating center to effector.
What is the effector in the Reflex Arch?
Muscle or gland that responds to motor nerve impulses.
What are the Enlargements of the spinal cord?
How many nerves are there in the thoracic nerve and what does it do?
12 pairs. Helps with breathing.
What are intercostal nerves?
They directlyconnect to the structures they supply in the intercostal spaces. The anterior rami of spinal nerves do not enter into the formation of plexuses.
Which connective tissue covering wraps individual axons?
Which connective tissue covering wraps around fascicles?
Which connective tissue covering covers the entire nerve?
What are meningeal branches?
A branch that reenters the vertebrate cavity through the invertebral foramen and supplies the vertebrae, vertebral ligaments, blood vessels of the spinal cord, and meninges.
What does reciprocal innervation do?
Prevents conflict between opposing muscle and is vital in coordinating body movements.
What is the brain stem?
It is continuous with the spinal cord and consists of the medulla oblongata, pons, and midbrain.
What is the blood brain barrier?
Consists mainly of tight junctions that seal together the endothelial celss of brain blood capillaries.
Protects brain from harmful substances and pathogens.
Allows O2 and CO2 to enter.
What is CSF and what is its job?
A clear liquid composed primarily of water that protects the brain and spinal cord from chemical and physical injuries.
Carries small amount of oxygen, glucose, etc from blood to neurons and neuroglia.
What produces the majority CSF?
Choroid Plexus(networks of blood capillaries in the walls of all the ventricles)
Vestibulocochlear nerves (VIII)
Special sensory that convey impulses related to hearing and equilibrium.
Vagus Nerve (X)
A sensory motor that decreases heart rate, allows swallowing, vocalizing, coughing, taste from epiglottis, monitors blood pressure, oxygen, and CO2 in blood.
Oculomotor nerve (III)
A somatic and motor nerve that controls movement of the eyeballs and upper eyelids. They adjust lens for near vision (Accomadation).
Where are the cell bodies of sensory neurons that enter the spinal cord?
Spinal ganglia or dorsal root ganglia.
What are the main parts of the Brain?
Brain stem, cerebrum, cerebellum, Diencephalon
What is Hemispheric Lateralization?
Anatomical, physiological differences in tow hemispheres.
What are association tracts?
Contains axons that conduct nerve impulses between gyri in the same hemisphere.
A sensory nerve that contains axons that conduct nerve impulses for vision.
Trigeminal Nerve (V)
A sensory and motor nerve that senses touch, pain and thermal sensation from scalp, face, and oral cavity.
*The largest cranial nerve
What are Pacinian Corpuscles?
large oval structures that are composed of a multi-layered connective tissue capsule that encloses a dendrite.
What are nociceptors?
They respind to painful stimuli resulting from physical or chemical damage to tissue.
What are commissural tracts?
Contains axons that conduct nerve impulses from gyri in one cerebral hemisphere to corresponding gyri in the other cerebral hemisphere.
Primary Somatosensory area
receives nerve impulses for touch, pressure, vibration, itch, tickle, temperature, pain and proprioception.
*Located postcentral gyrus of parietal lobe.
Primary auditory cortex
receives aid for sound and is involve in auditory.
*Located in occipital lobe
Primary olfactory area
receives impulses for smell and is involved in olfactory perception.
What are Merkel discs?
saucer shaped flattened free nerve endings that make contact with Merkel Cells of the statum basale.
*In fingertips, hands, and lips.
Primary motor area
In the precentral gyrus of the frontal lobe.
Decides what movement sent down spinal cord to effectors.
What are Ruffini Corpuscle?
Elongated encapsulated receptors located deep in the dermis and in ligaments and tendons
*present in hands and sensitive to stretching.
Primary visual area
Receives visual information and is involved in visual perception.
What are Meissner Corpuscles?
They are touch receptors that are located in the dermal papillae of hairless skin.
Receives information from primary auditory area
Secretes the hormone Melatonin.
*size of a pea
*Pine cone like
What is a Folia?
series of slender parallel folds
The superior enlargement. Extends from the fourth cervical vertebra C4 to the first thoracic vertebra T1.
The inferior enlargement. Extends from the ninth to twelfth thoracic.
Inferior to the lumbar enlargement. The spinal cord terminates as a tapering, conical structure. Ends at the level of the inter vertebral disc between the first and second lumbar vertebrae.
Arising from the conus med