Week 4: Introduction to Sensation Flashcards
what is sensation ?
sensation refers to the process of detecting and receiving stimuli from the environment through our sensory organs like the eyes, ears, skin, nose, and tongue via specialized receptors.
what is perception ?
perception is the process by which our brain interprets and makes sense of the sensory information received from our environment.
sum up sensation vs. perception.
sensation is the process of detecting stimuli from the environment through our sensory organs. perception is the brain’s interpretation of that sensory information, allowing us to make sense of it and form meaningful experiences, thoughts, or understanding of the world.
what are the general senses ?
somatic senses refer to sensations coming from the skin, muscles, joints, and bones. ex: all tactile senses, pain, proprioception.
visceral sense: conscious/subconscious sensation of internal organs.
example: touch, vibration, pressure, pain, knowing hand is in the air without seeing it, hunger, nausea, fullness, bp, breathing.
what are the special senses ?
olfaction, taste, vision, hearing, equilibrium, and balance.
what is the basic mechanism of sensation ?
- stimulation of sensory receptor: stimulus reaches a sensory receptor in the body and it undergoes a conformation change.
- signal transduction: when the receptor undergoes a conformation change, it causes a change in membrane potential. it converts the stimulus into an electrical signal called an action potential.
- transmission of signal: action potential travels along the axon of a sensory neuron to the central nervous system.
- integration of sensation: the electrical signal arrives at the cns, where it is processed and interpreted by other neurons.
what is a first order neuron ?
a first order neuron is the initial neuron in the sensory pathway that carries sensory information from the peripheral nervous system into the central nervous system.
different types of sensory receptors and their relationships with first order neurons ? a
a) first order sensory neuron with free nerve endings: the sensory neuron has free nerve endings. the sensory receptor proteins are found in the dendrites and generate an action potential. the action potential then travels along the axon resulting in the release of some sort of neurotransmitters into a synapse with a neuron in the central nervous system.
examples of neurons that have these: pain, temperature, tickle, and touch.
all sensory neurons are arranged ?
in a unipolar fashion. a unipolar neuron is a neuron with a single process that branches into a dendrite and an axon.
different types of sensory receptors and their relationships with first order neurons ? b
b) first order sensory neurons with encapsulated nerve endings.
the dendrite is not free but is embedded in a connective tissue capsule to magnify a particular sensation.
- good for pressure and vibration.
- pacinian corpuscles found in the dermis.
different types of sensory receptors and their relationships with first order neurons ? c
c) sensory receptor synapses with first order sensory neuron.
highly specialized sensory receptor cell that will receive a signal, make a decision to generate action potential, and if the action potential is generate, the neurotransmitter is released at the synapse with the dendrite of the first order neuron.
difference between a/b with c ?
in the first two examples, dendrites detect the stimulus: first order sensory neuron with free nerve endings or encapsulated nerve endings to magnify stimulus. sometimes instead of first order neuron detecting stimulus directly, there are specialized cell that synapses with the first order neuron to tell it whether or not they should send a signal to the central nervous system.
what are exteroceptors ?
sensory receptors that detect external stimuli from the environment. found on the surface of the body: includes all skin and special senses.
what are interoceptors ?
sensory receptors that detect internal stimuli from within the body. they are found in internal organs, blood vessels, etc.
- usually not conscious of stimuli detected by these receptors.
what are proprioceptors ?
sensory receptors that provide information about the position and movement of the body. they are found in the muscles, tendons, joints, and inner ear.
what are mechanoreceptors ?
mechanoreceptors are sensory receptors that detect mechanical stimuli like touch, pressure, vibration, etc. these changes are detected when something physically touches or moves the skin.
what are thermoreceptors ?
thermoreceptors detect changes in temperature. they then send send electrical signals through sensory neurons to the brain. the brain then triggers an appropriate response: shivering,sweating, constriction/dilation of blood vessels.
what are nociceptors ?
sensory receptors that detect pain or harmful stimuli.
what are photoreceptors ?
change their conformation in response to light, found mainly in the retina.
what are chemoreceptors ?
chemoreceptors are sensory receptors that detect chemical changes in the environment or in the body. important for blood oxygen levels.
what are osmoreceptors ?
sensory receptors that detect changes in osmolarity/concentration of solutes in the blood.
what is adaptation ?
the process by which sensory receptors become less sensitive to a constant stimulus over time. this can allow the body to focus on newer more significant stimuli in the environment.
what are rapidly adapting receptors and slowly adapting receptors ?
rapidly adapting receptor: these receptors respond quickly to stimulus, but they decrease their response quickly if the stimulus remains constant. an example of this is wearing a watch or sitting in a warm bathtub.
slowly adapting receptor: things that you will be aware of even if the stimulus is sustained for a long period of time. example: noxious stimuli, sitting in a burning hot bathtub, freezing cold bathtub.
