05. Animal Form and Function [DEFINITIONS] Flashcards
Ventricles
Ventricles are the four irregular shaped cavities formed by the central canal in the brain.
Autonomic Nervous System
The nervous system that controls the involuntary activities of the body consisting of neurons which carry impulses to control activities of smooth muscles, cardiac muscles, and glands is the autonomic nervous system.
Motor System
The nervous system that consists of neurons that carry nervous impulses to skeletal muscles controlling voluntary activities is the motor system.
Resting Potential
When a neuron is at rest (when not sending a signal/non conducting), the membrane potential is called the resting potential.
Action Potential
An action potential occurs due to a change in membrane potential above a threshold value due to a stimulus.
Depolarization
Depolarization is a change in the cell’s membrane potential such that the inside of the membrane is made less negative relative to the outside which is resulted from Na+ inflow in response to a stimulus.
Repolarization
Repolarization is when sodium channels close, blocking Na+ inflow. Here, most potassium channels open permitting K+ outflow, making the inside of the cell negative.
Hyperpolarization
Hyperpolarization is when sodium channels are closed but potassium channels are opened, resulting in the inside of the membrane being more negative.
Refractory Period
A refractory period is the short time immediately after an action potential where the neuron cannot respond to another stimulus, because of the inactivation of sodium channels. This prevents the reverse conduction of an impulse in an axon.
Synapse
A synapse is the junction where a neuron (presynaptic cell) communicates with another cell (postsynaptic cell) across a narrow gap (synaptic cleft)
Postsynaptic Cell
A postsynaptic cell is a cell that may be another neuron, muscle cell or secretory cell.
Chemical Synapse
The junction where one neuron communicates with the next cell using a chemical (neurotransmitter) is called a chemical synapse.
Electrical Synapse
Some neurons can also communicate through direct electrical connections. This is called an electrical synapse.
Neurotransmitters
Neurotransmitters are the molecules that are released from the synaptic terminals of presynaptic neuron and diffuse across the synaptic cleft, bind with the receptors at the postsynaptic membrane triggering a response.
Reflex Arc
Reflex arc is the functional unit of the vertebrate nervous system.
Sensory Neuron
A sensory neuron transmits impulses from a sensory receptor to the central nervous system.
Interneuron
The central nervous system synapses with an associated neuron called interneuron.
Motor Neuron
When an impulse is transmitted to a motor neuron by the interneuron, the motor neuron conveys the signal to effector tissues/organs.
Sensory Receptor
A sensory receptor is a specialized structure such as a specialized cell, organ or a subcellular structure which can detect a specific stimulus and convert the stimulus energy to a changing membrane potential to be transmitted to the central nervous system as action potentials for sensory perception and interpretation.
Chemoreceptors
Chemoreceptors are sensory receptors that respond to chemical stimuli
Taste receptors
Receptors that detect the five basic sensations (sweet, sour, bitter, salt, and umami- savory taste) are taste receptors
Olfactory Receptors
Olfactory receptors are cells located within the epithelium of the upper portion of the nasal cavity detecting odors
Thermoreceptors
Specialized temperature sensitive receptors which detect heat and cold on the body surface and in the internal environment of the body are thermoreceptors.
Photoreceptors
Photoreceptors are sensory receptors that are sensitive to light