The Senses Flashcards
What are the senses essentially?
Sensory organs convert energy they receive into an action potential that is carried to the CNS by the neurons in the PNS where it is interpreted and sent back to the PNS as a message
What is the stimuli for the senses?
Forms of energy
What are the steps of a sensory pathway?
Sensory reception, sensory transduction, sensory transmission, sensory perception
What is sensory reception? What are the inside and outside types of receptors?
- Detect stimulus
- Inside- pH (medulla for breathing), body position, blood pressure, etc
- Outside- temperature, pain, pressure, light, chemical receptors
What is sensory transduction/ how does it work?
Chemical binding which cause physical deformation (more pressure=more action potential), causes conversion to a change in membrane potential to create an action potential, also travel on distinguished neurons to determine senses
Transmission
Action potential to CNS
Perception
CNS makes sense of the message
5 different types of receptors
- Mechanoreceptors- sense physical deformation
- Chemoreceptors- sense molecules
- Electromagnetic receptors- sense light
- Thermoreceptors- sense heat
- Pain receptors- highest amount in skin but in other organs too
What is hearing?
Vibrations in air, sensed by mechanoreceptors on hair cells
Auditory canal
Focus vibrations on a point
Wax
Protect ear from pathogens
Tympanic membrane
Ear drum, vibrates
Smallest bones in ear
Malleus, incus, stapes
Cochlea
Fluid that maintains positional equilibrium. Hair cells vibrate here and generate action potential from auditory nerve to the brain
Eustachian tube
Where fluid could build up and cause inflammation to nose, throat, and ear
Volume
Amplitude of sound waves
Pitch
Frequency of sound waves
How do we smell and taste
In the nasal cavity and on the tongue, we have chemoreceptors. On the tongue they are found on the taste buds. The tongues tastes sweet, sour, bitter, salty, and savory. A chemical binds to a chemoreceptor and cause a change in membrane potential so an action potential is sent to the brain on dedicated neurons to that sense
How do we see?
- Have to have some light to see
- Light comes in through pupil which regulates how much light is let through
- Lens bend light into photoreceptors on retina (inside layer of eye)
- 2 types of photoreceptors receive it: cones and rods. Rods sense light. Cones see colors red, green, and blue.
- Each contains retinal and opsin, proteins, and rods have rhodopsin as well. These proteins change shape and cause an action potential from the optic nerve to the brain.
Color blind
common in guys cause only have to have it on X chromosome but in ladies they have to have it on both X chromosomes
Optic nerve
Sends message to brain
Optic disk
Blind spot, where optic nerve connects to eye
Choroid
Pigmented layer, middle layer between sclera and retina
Retina
Inside layer, contains photoreceptors
Ciliary muscles
Allows iris to open and close dead ing on the light to focus on something
Aqueous humor
Watery fluid between cornea and pupil
Cornea
Covering of eye which is covered by the sclera
Sclera
Outer layer, very tougg
Vitreous humor
Inside of eye, thick
Lens
Refract and bend light
Iris
Part of choroid, controls how much light enters your eye by opening and closing the the pupil, colored part
muscle movement
- action potential travels from brain along neuron to a motor neuron
- neurotransmitters (acetylcholine) cross the synapse
- they bind to ligand-gated channels on muscle causing Na channels to open and generate action potential into the muscle’s plasma membrane
- travels down to T tubules, causing calcium ions to be release
- calcium binds to troponin and exposes the binding sites by taking tropomyosin (actual thing that covers binding site) with it
- myosin binds to binding site, pulling actin together
- actin contracting means sarcomere contracts then whole muscle fiber contracts and then the whole muscle
