Chapter 23 Flashcards
What is the overarching function of sensation?
- maintains homeostasis
- receptors are specific to certain sensations
General sense organs vs. special sense organs
-what is the difference? Where are they distributed?
-general sense organs: somatic; in skin, mucus, connective tissue, muscles, tendons, joints, viscera; touch
What is the process of sensation?
- stimulation of sensory receptor
- transduction of the stimulus
- generation of nerve impulses
- integration of sensory input
What is the function of a sensory receptor?
- detect changes in our internal and external environments
- help maintain homeostasis
How do sensory receptors convert the stimulus into an electrical impulse?
- the action potential
- mechanoreceptor
What is adaptation? Why is it important?
- receptor potential decreases over time in response to a continuous stimulus
- helps with overstimulation
How does adaptation work?
-the frequency of the action potentials decrease
What types of adaption are there? Examples
- fast: pressure, touch smell; feeling your clothing
- slow: pain, body position, chemical position of the blood
Which receptors are fast and which are slow at adapting?
- fast: thermoreceptor, root hair plexus, tactile corpuscle, bulboid corpuscle, pacinian corpuscle
- slow: bulbous/ruffini corpuscle, merkel disc, nociceptors
What is the two point discrimination test?
-measures the distance between two points are sensed at separate points
What areas would have a smaller distance between the two points? Larger?
- Smaller: tongue, finger
- Larger: shoulder
What are the three location receptors?
- Exteroceptors
- Visceroceptors
- Proprioceptors
Where are the exteroceptors located? Function? Examples?
- on or near the body surface
- respond to stimuli external to the body
- pressure, touch, pain, temperature
Where are the visceroceptors located? Function? Examples?
- located internally within the viscera
- provide information about the internal environment; detect pressure, stretching, and chemical changes
- blood vessels, intestines, urinary bladder, hunger, thirst
Where are the proprioceptors located? Function? Examples?
- in skeletal muscles, joint capsules, tendons
- give information about body movement, orientation in space, and muscle stretch
- muscles and tendons
What are the stimulus receptors?
- Mechanoreceptor
- Chemoreceptor
- Thermoreceptor
- Nociceptor
- Photoreceptor
- Osmoreceptor
What stimulus does the mechanoreceptor detect? Examples of the stimulus?
- stimuli that deform the receptor
- pressure applied to skin or blood vessels
- pressure caused by stretch or pressure in muscle, tendon, or lung tissue
What stimulus does the chemoreceptor detect? Examples of the stimulus?
- change in concentration of certain chemicals
- taste, smell, CO2, blood glucose level
What stimulus does the thermoreceptor detect? Examples of the stimulus?
- changes in temperature
- warm or cold air or water
What stimulus does the nociceptor detect? Examples of the stimulus?
- intense pain
- TISSUE DAMAGE
- toxic chemical, intense light, sound, pressure, heat
What stimulus does the photoreceptor detect? Examples of the stimulus?
- light
- ONLY in the eye
What stimulus does the osmoreceptor detect? Examples of the stimulus?
-levels of osmotic pressure in body fluids
change of concentration of electrolytes
-stimulates the thirst center in the hypothalamus
-ONLY in hypothalamus
What are the different structures of receptors?
- free nerve endings
- encapsulated nerve endings
Which structure of receptor is more common?
- free nerve endings are more common
- encapsulated are normally only mechanoreceptors
What types of receptors have free nerve endings?
- nociceptors
- thermoreceptors
- hair root plexus
- merkel disc
What types of receptors have encapsulated nerve endings?
- mechanoreceptors
- Meissner’s corpuscle
- bulboid corpuscle
- ruffini corpuscle
- pacinian corpuscle
Why do we need to have pain?
-alerts us to threats in our environment
What are each type of pain?
- acute/fast A
- chronic/slow B
Where is each type of pain located?
- acute/fast A: skin, mucous membrane, anywhere superficial
- chronic/slow B: visceral
Which receptors detect pain and what’s their structure?
- nociceptors
- free nerve endings
What is diabetic neuropathy?
- nerve damage that can occur if your blood sugar gets too high
- most often occurs in feet and legs
- can lead to amputation
What is fibromyalgia? What does Lyrica do?
- chronic, widespread musculoskeletal pain
- abnormal amplification of pain information
- Lyrica blocks calcium influx so the nerves cannot release neurotransmitters
What is referred pain? How does it work? Example?
- when the stimulation of pain receptors in the viscera is felt as a pain the skin
- sensory info from the viscera enters the spinal cord at the same spot that it would from the skin. this causes the brain to believe that in most cases it’s the skin that is hurting
- heart attack
What type of receptor detects temperature and what’s their structure?
- thermoreceptor
- free nerve endings
Warm vs. cold receptor
- Warm: in dermis
- Cold: in the deepest layer of the epidermis
What happens when it gets below 10 degrees C? Above 118 degrees C?
- anesthetic effect, numbness (decreased frequency of action potential)
- burning pain
Sense of touch
-free and encapsulated
Where are the sense of touch receptors found in the body?
- hair root plexus: free nerve endings; wrapped around a hair shaft; rapid adaptation
- itch: chemical irritation of free nerve endings
- tickle: free nerve endings, perception
Where in the integumentary system are they found?
- epidermis
- dermis
What does light touch? Nerve endings? Made of? Adaptation?
- tactile or merkel disk
- free nerve endings
- tactile epithelial cells and tactile disk(sensory neuron)
- slow adaptation
What are the deep touch receptor? Location? Nerve endings? Adaptation?
- tactile/meissner’s corpuscle: dermal papillae, encapsulated, rapid adaptation
- bulboid corpuscle: mucous membrane, encapsulated, rapid adaptation
- ruffini corpuscle: deeper dermis, encapsulated, slow adaptation; holding steering wheel
- pacinian/lamellar corpuscle: deep dermis, encapsulated, rapid adaptation
What do muscle spindles do?
-they prevent a muscle from tearing
What do muscle spindles detect?
-they detect stretch
What do intrafusal fibers do? What motor neurons innervate them? Where are they located?
- detect stretch
- innervated by alpha motor neurons
- located between and parallel to regular muscle fiberas
What do golgi tendon organs do? How are they stimulated? Where are they located?
- Cause the skeletal muscle to relax (so only one is contracting at a time
- Stimulated by stretch of a tendon
- Located between muscle and tendon
