Sensation-Wingerd Chap 9
Sensory Functions - Concept 1
What are the 2 general senses? Somatic senses and visceral senses
What is the difference between somatic and visceral senses? Somatic senses recognize touch, pressure, temperature, pain, and body position and visceral senses provide information about internal organs
What are special senses? Senses embedded in organs in head (olfactory epithelium, the papillae of the tongue, the eye and the ears)
Sensory Receptors - Concept 1
How is a stimulus converted to a nerve impulse? Sensory receptors such as a modified dendrite in sensory neuron conduct impulse to CNS.
Name the 5 sensory receptors. Mechanorecptors, thermoreceptors, nociceptors, photoreceptors, chemoreceptors
What is the threshold level rising as the stimulus continues called? Sensory adaptation
Sensory Pathways - Concept 1
What are the 2 sensory pathways? General sensory pathways, Special sensory pathways (GSP, SSP)
What is the difference between the general and special sensory pathways? GSP's -simple receptor-skin, visceral organs, muscles to brain. SSP's -complex receptor- special senses eyes, ears, nose, tongue.
What is the conduction pathway for GNS? Dorsal column-medial lemniscus pathway and Anterolateral (spinothalamic pathway) - 3 sensory neurons - 1st, 2nd, and 3rd order neurons.
What is the conduction pathway for SSP? At least 3 sensory neurons that connect the receptors with specific regions of the cerebral cortex.
Motor Origins - Concept 1
What are the 6 motor origins of the CNS? Spinal cord, Brain stem, Cerebellum, Basal ganglia, Hypothalamus,and Cerebral Cortex.
What motor origin site includes somatic reflexes that stimulate skeletal muscle contraction and visceral reflexes? Spinal Cord
What motor origin site is located in the nuclei in the medulla oblongata, pons, and midbrain and cause coughing, sneezing, breathing, change in heart rate and vomiting? Brain Stem
What motor origin site are clusters of gray matter within the cerebrum and control semi-voluntary movements like laughing, walking, and jumping? Basal Ganglia
What motor origin site contains integration centers within its gray matter and receive sensory information from the inner ear, control body posture, balance, and coordination? Cerebellum
What motor origin site is the center for involuntary control that lead to smooth muscle, cardiac and glands? Hypothalamus
What motor origin site represents the highest level of integration and is originating site for memory, skillful body coordination, and precise muscular movements? Cerebral Cortex
Motor Pathways - Concept 1
Where do somatic motor pathways originate from? Primary motor cortex
In a somatic motor pathway, the lower motor neuron terminates at Skeletal muscle effectors
Where do the upper motor neuron and lower motor neuron synapse? Anterior gray horn of the spinal cord
General Senses - Concept 2
What are the 2 nerve endings for the sensory receptors of the general senses? Encapsulated nerve endings and free nerve endings.
What are the receptors in the skin for touch? Tactile (Meissner) corpuscles - light touch, Tactile disc (Merkel receptor) - touch, texture , Ruffini corpuscles - stretch, and Lamellar (Pacinian) corpuscles - deep pressure.
Name the free nerve endings in the skin. Pain, touch, temperature
What sensory receptor detects pain? Nociceptors that are believed to be sensitive to chemicals rleased during and even involving damage or destruction of cells.
How is pain classified? Superficial somatic pain (pinch or skin prick), Deep somatic pain (skeletal muscles, joints, tendons or fascia, Visceral pain (visceral organs)
Why is visceral pain more difficult to trace to its source? Because major nerve pathways share impulses from different parts of the body in a phenomenon called referred pain.
Body Position - Concept 2
What are the receptors of body position called? Proprioceptors
What is the proprioceptor for skeletal muscle? Muscle spindles that are specialized muscle fibers associated with sensory neurons and monitor length of skeletal muscle.
What is the proprioceptor between a tendon and skeletal muscle? Tendon organs (encapsulated) that are stimulated by tension in the surrounding tendon.
Where are other proprioceptors besides muscle spindles and tendon organs located? Joints, and inner ear.
Olfactory Structures - Concept 3
Where are the olfactory receptors located? Mucous membrane of the nasal epithelium.
What do columnar epithelial cells do in nasal epithelium? They provide support for each neuron.
What do basal cells cells do in nasal epithelium? Located between the bases of supporting cells, the reproduce to make new olfactory receptors.
What do olfactory hairs do in nasal epithelium? These cilia are located at the end of the olfactory cells and extend into the mucus membrane.
What produces the mucus in the connective tissue deep to the olfactory organs? The olfactory glands.
What is at the base of the olfactory glands? At their basal end the axon from each neuron extends thru the cribriform plate of the ethmoid bone and terminates at the olfactory bulb of the brain.
Olfactory Pathway - Concept 3
Where does the conduction pathway for smell begin? The olfactory hairs of the receptor cells.
What are the steps of the olfactory pathway? Gas molecules dissolve in mucus→olfactory hairs→action potential→nasal epithelium→cribriform plate into cranial cavity→olfactory bulbs→frontal lobe of cerebral cortex
What kind of receptor is the olfactory organ? Chemoreceptor
Gustatory Structures - Concept 3
How many taste buds are on the surface of the tongue? approx. 10,000
What are the small elevation of the taste buds called? Papillae
Where are other organs of taste located? Roof of the mouth and walls of the pharynx.
What are the group of taste receptor cells called? Gustatory cells.
How are gustatory cells formed? Each taste bud consists of gustatory cells which are surrounded by epithelial cells.The free end has gustatory microvilli which project thru an opening in the taste bud known as a taste pore.
What are the five primary types of taste sensations? Sweet, sour, bitter, salty and umami.
Gustatory Pathway - Concept 3
What is the basic gustatory pathway? Begins at binding to gustatory cells and goes thru at fibers of facial, glossopharyngeal and vagus nerves (Cranial Nerves VII, IX and X) and ends at cerebral cortex.
Sight - Concept 3
What are the accessory structures of the eye? Eyelids, eyelashes, conjunctiva, lacrimal apparatus, lacrimal gland, lacrimal canals, lacrimal sac, nasolacrimal duct and extrinsic muscles.
Where is the conjunctiva located? Inner mucous membrane of eyelid and folds back to cover anterior surface of the eye as well. Secretes mucus.
What does the lacrimal apparatus consist of? Lacrimal gland, lacrimal sac and nasolacrimal ducts.
Trace the path of tears. Secreted by lacrimal gland and collected by lacrimal canals that channel into lacrimal sac within the lacrimal bone and pass into nasolacrimal duct.
What are the benefits of tears? Salt solution that moistens and lubricates and contain an antibacterial enzyme.
Structure of the Eye - Concept 3
What are the tunics (layers) of the eyeball? Outer fibrous tunic, middle vascular tunic and inner nervous tunic.
What is the thick outermost layer of the eyeball called? Fibrous tunic which contains posterior sclera and anterior cornea.
What makes up the 'white of the eye'? The sclera of the fibrous tunic which is white, fibrous connective tissue. Posterior portion is penetrated by the optic nerve. Holds eye shape.
What is the cornea? Transparent window of the eye that light must pass through. Lacks blood vessels.
What is the vascular tunic? Part of eye that contains most blood vessels - includes choroid, ciliary body, the iris and the lens.
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