Download Anatomy and Functioning of the Nervous System: From Sensory Input to Motor Output and more Quizzes Physiology in PDF only on Docsity!
2 organs systems that maintain internal
coordination (1)
1.Endocrine System: Communicated by means of chemical
messengers (hormones) secreted into the blood2. Nervous
System: Employs electrical and chemical means to send
messages very quickly from cell to cell.
TERM 2
3 steps for coordinating tasks
DEFINITION 2
1. Through sense organs and simple sensory nerve endings, it receives info about changes in the body and the external environment and transmits coded msgs to the CNS (central nervous system) 2. The CNS processed this info, relates it to past experience, and determines what response (if any) is appropriate to the circumstances 3. The CNS issues commands primarily to muscle and gland cells to carry out such responses. TERM 3
2 major anatomical subdivision of Nervous
System (3)
DEFINITION 3
1. Central Nervous System (CNS): consists of the brain and
spinal cord, which are enclosed by the cranium and vertebral
column. 2. Peripheral Nervous System (PNS): Consists of all
the rest; of nerves and ganglia.
TERM 4
Nerve & Ganglion
DEFINITION 4
Nerve: A bundle of nerve fibers (axons) wrapped in fibrous
connective tissue. They emerge from the CNS through
foramina of the skull and vertebral column and carry signals
to and from other organs of the body.Ganglion: Knot-like
swelling in a nerve where the cell bodies of neurons are
concentrated.
TERM 5
PNS is divided into SENSORY & MOTOR
divisions (which are also subdivided)- 5
DEFINITION 5 Sensory (aka afferent) division: carries signals from various receptors (sense organs and simple sensory nerve endings) to the CNS. This pathway informs the CNS of stimuli within and around the body. Somatic Sensory division: carries signals mainly from the receptors in the skin, muscles, bones, and joints Visceral sensory divisions: carries signals mainly from the viscera of the thoracic and abdominal cavities, such as the heart, lungs, stomach, and urinary bladder
Motor Division-
aka Efferent. It carries signals from the CNS to gland and muscle cells that carry out the body's responses. Cells and organs that respond to command's from the nervous system are called effectors. Somatic motor division: carries signals to the skeletal muscle. This output produces muscular contraction that are under voluntary control, as well as involuntary contractions called somatic reflexes TERM 7
BULLET CNTD FROM SOMATIC MOTOR
DIVISION-
DEFINITION 7
- Visceral motor division (aka ANS-Autonomic Nervous System)- Visceral motor division (aka ANS-Autonomic Nervous System)It carries signals to glands, cardiac muscle, and smooth muscle. We usually have no voluntary control over these effectors, so the ANS operates at an unconscious level. The responses of the ANS and its effectors are called visceral reflexes. Its subdivided into: Sympathetic division: tends to arouse the body for action, ex: accelerating heartbeat and increasing respiratory airflow, but inhibits digestion Parasympathetic division: tends to have a calming effect, ex: slowing heartbeat but stimulates digestion TERM 8
Electrophysiology-
DEFINITION 8
Cellular mechanisms for producing electrical potential and
currents.
TERM 9
Electron Potentials-
DEFINITION 9
Difference in the concentration of charged particles between
two points. Its a form of potential energy that under the right
circumstances can produce a current (flow of charged
particles from one point to another)-As long as the battery
has a potential (voltage) we say it is polarized
TERM 10
Resting Membrane Potential-
DEFINITION 10
aka RMP-Charge difference across a plasma membrane
Refractory Period-
- Refers only to a small patch of membrane not an entire neuronPeriod of resistance to re-stimulation where it is difficult or impossible to stimulate the region of a neuron to fire again. Divided in 2 phases:1.Absolute period: No stimulus of any strength will trigger a new action potential, followed by...2. Relative Refractory period: It is possible to trigger a new action potential, but only with an unusually strong stimulus. The absolute lasts from the time that Na+ are open until they are inactivated. The relative lasts until hyperpolarization ends. TERM 17
Synapses-
DEFINITION 17 Neuron to neuron. Signals here arrive at the synapse byway of:- presynaptic neuron: Releases a neurotransmitter. The next neuron which responds to it is called..-postsynaptic neuron.-The presynaptic neuron may synapse with a dendrite, soma, or the axon of a postsynaptic neuron, forming an axodendritic, axosomatic, or axoaxonic synapse, respectively. TERM 18
Chemical Synapse-
DEFINITION 18
-They can integrate info and make decisions. -Neurons
communicated by neurotransmitters.-Cross synaptic cleft?
TERM 19
Synaptic Transmission (Excitatory Cholinergic
Synapse)-
DEFINITION 19
-Cholinergic synapse: a gap where a neuron that produces
acetylcholine (ACh) sends messages to other neurons, or to
skeletal muscle cells.This type of synapse is essential to
muscle movement.
TERM 20
Synaptic Transmission (Excitatory Adrenergic
Synapse)-
DEFINITION 20
Gap where neuron that produces norepinephrine (NE)
neurotransmitters aka noradrenaline.
Synaptic Transmission (Inhibitory GABA-ergic
Synapse)-
-Employs GABA as its neurotransmitter. It works the same as ACh where it binds to ion channels and causes immediate changes in immediate changes in membrane potential. The release of GABA and binding to its receptor are similar to the preceding case. However, the GABA receptors is a chloride channel. When it opens, Cl- enters the cell and makes the inside even more negative than the resting membrane potential. The neuron is therefore inhibited, or less likely to be fired. TERM 22
Neural Circuits-
DEFINITION 22 The pathways among its neurons. 4 kinds:1. Diverging circuit: One nerve stimulates several fibers2. Converging circuit: Input from many nerve fibersto one neuron3. Reverberating: linear sequence; prolonged repetitive effect until a neuron fails to fire. used in short term memory and maybe epilepies4. Parallel after-discharge: input neuron diverges to stimulate several chains, re-converge in single output neuron. Explains why you can stare at a light, close your eyes, and cont. to see it. This continued firing after the stimulus stops is aka after-discharge TERM 23
Synaptic Plasticity-
DEFINITION 23
The ability of synapses to change. They can be created or
deleted in as little as 1-2 hours. Synaptic potential is the
process of making transmission easier.
TERM 24
Immediate Memory-
DEFINITION 24
The ability to hold something in mind for just a few seconds.
By remembering what you just happened, we get a feeling
for the flow of events and a sense of the present. This kind of
memory is indispensable to the ability to read.
TERM 25
Short-Term Memory-
DEFINITION 25 Lasts from a few seconds to a few hours. Info stored in the STM may be quickly forgotten if we stop mentally reciting it. Working memory is a form of STM that allows us to hold an idea in min long enough to carry out an action such as calling a cell # we just looked up, doing math probz, searching for lost keys while remembering where we already looked. It is limited to small amount of info.
