what types of sensory receptors are there ?
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Nervous System (Senses). What types of sensory receptors are there ?. Mechanoreceptors Chemoreceptors Thermoreceptors Nociceptors Photoreceptors. Somatic Visceral General Special Exteroreceptors Enteroreceptors Proprioceptors Encapsulated Unencapsulated. Nervous System (Senses). - PowerPoint PPT PresentationTRANSCRIPT
What types of sensory receptors are there?
Nervous System (Senses)
Somatic
Visceral
General
Special
Exteroreceptors
Enteroreceptors
Proprioceptors
Encapsulated
Unencapsulated
Mechanoreceptors
Chemoreceptors
Thermoreceptors
Nociceptors
Photoreceptors
What are the types of cutaneous sense organs?
Nervous System (Senses)
What is the network-like pattern on fish and tadpoles?
Nervous System (Senses)
Neuromasts have sensitive hair cells with kinocilia extending into a cavity, fluid or a cupula
Organized into mechano- or electroreceptive structures
Pattern refered to as a lateral line (canal) or cephalic canal
The Senses: Balance
Kinetic labyrinth
Responds to movement of endolymph (fluid) in semicircular canals i.e. angular (rotational) acceleration
Nervous System (Senses)
The Senses: Balance
Static labyrinth
Responds to force of gravity and linear acceleration
Nervous System (Senses)
The Senses: HearingAuricle collects sound waves
External auditory meatus (canal) channels sound waves
Tympanic mem. & ossicles conduct sound waves
Nervous System (Senses)
The Senses: Hearing
The oval window transfers sound waves to the liquid inside the cochlea
Three scala:vestibulimedia (cochlear duct)tympani
Nervous System (Senses)
The Senses: HearingSound waves vibrate basilar membrane causing microvilli to bend
Bending causes depolarization in hair cells that in turn create action potentials in synapsing neurons
Nervous System (Senses)
The Senses: HearingBasilar membrane stiff near vestibule, responds to higher frequency sounds (20,000 Hz).
Lower pitches picked up further in to cochlear duct, with lowest frequencies (200 Hz) at apex
Excess wave energy travels back down via scala tympani and out round window
Nervous System (Senses)
The Special Senses: Olfaction (smell)Nervous System (Senses)
The Special Senses: Gustation (taste)
Chemoreceptors that detect chemicals which are in solution (saliva) are taste buds.
Taste buds are comprised of specialized epithelial cells that synapse with neurons.
Associated mainly with papillae.
Also on lips etc.
Nervous System (Senses)
The Senses: Gustation (taste)
Types of papillae:
Circumvallate
Foliate
Fungiform
Filiform (most numerous but NO taste buds here. Foliate papillae
Nervous System (Senses)
The Senses: Gustation (taste)
Salty
Nervous System (Senses)
What are the layers of the eye and what are their functions?3 distinct layers of tissue in eye:
FibrousSclera & cornea
VascularChoroid, iris etc.
NervousRetina
Clear light pathway
Nervous System (Senses)
What is the external anatomy of the eye?Nervous System (Senses)
What is the internal anatomy of the eye?Nervous System (Senses)
How do our eyes control the amount of light entering?
Cornea refracts light as it head towards lens
Iris is attached to ciliary body and consists of contractile tissue (smooth muscle). Coloration is due to varying amounts of melanin
Pupil is simply the hole in the center of the iris
Nervous System (Senses)
How do we focus the image?Ciliary body contains smooth muscle fibers, which allow the distortion of the lens via suspensory ligaments.
Ciliary processes are very vascular and produce aqueous humor (watery fluid in anterior compartment).
Nervous System (Senses)
How is light converted into action potentials?
3 neuronal layers of the retina:Photoreceptors
Also bipolar neurons and Ganglionic neurons
Nervous System (Senses)
Are all photoreceptors created equally?Rods (~120 million each)
Cones (~6-7 million each)
Nervous System (Senses)
The Senses: Vision
Photoreceptors are rather unique in that they are hyperpolarized as a result of stimulation.
In dark (no stimulus) leaky Na+ channels.
In light (stimulus) Na+ channels close and hyperpolarization occurs
How is light converted into action potentials?Nervous System (Senses)