Sensory Receptors, Skin Structure, and Function in Human Physiology
Studied by 0 people
Call Kai
Learn
Practice Test
Spaced Repetition
Match
Flashcards
Knowt Play1/166
There's no tags or description
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced |
|---|
No study sessions yet.
167 Terms
Definitions
Q: What is a sensory receptor?
A specialized structure that detects a specific type of stimulus and converts it into an electrical signal (transduction).
Q: What is transduction?
A: The process where a receptor converts stimulus energy (light, chemicals, pressure, temperature) into a nerve signal.
Q: What is sensation?
A: Awareness of a stimulus at the receptor level before the brain interprets it.
Q: What is perception?
A: The brain's conscious interpretation of sensory information.
Q: What is a receptive field?
A: The area of skin or space monitored by one sensory neuron.
Q: What is sensory adaptation?
A reduced sensitivity to a constant stimulus over time.
Tonic vs. Phasic Receptors
Q: What are tonic receptors?
A: Slowly adapting receptors that keep firing as long as the stimulus is present (e.g., pain receptors, Merkel discs).
Q: What are phasic receptors?
A: Quickly adapting receptors that fire at the beginning of a stimulus then stop (e.g., smell receptors, Pacinian corpuscles).
Q: Application: Why do you stop noticing your perfume after a few minutes?
A: Olfactory receptors are phasic and adapt quickly.
Q: Application: Why does a sprained ankle hurt constantly?
A: Tonic pain receptors adapt slowly, so the signal continues.
Classification of Receptors
By Origin of Stimulus
Q: What are exteroceptors?
A: Receptors that detect external stimuli (touch, temperature, vision).
Q: What are interoceptors?
A: Receptors that detect internal conditions (blood pressure, pH, organ stretch).
Q: What are proprioceptors?
A: Receptors that detect body position and movement (muscle spindles, joint receptors).
By Modality (Type of Stimulus)
Q: What do mechanoreceptors detect?
A: Pressure, vibration, stretching, touch.
Q: What do thermoreceptors detect?
A: Temperature changes.
Q: What do chemoreceptors detect?
A: Chemicals (taste, smell, blood chemistry).
Q: What do photoreceptors detect?
A: Light (rods and cones).
Q: What do nociceptors detect?
A: Pain.
Q: What do baroreceptors detect?
A: Pressure changes in blood vessels or organs.
General vs. Special Sensory Receptors
Q: What are general sense receptors?
A: Simple receptors found throughout the body (touch, pain, temperature).
Q: What are special sense receptors?
A: Complex organs restricted to the head (vision, hearing, taste, smell, balance).
Q: Application: Why is vision a special sense?
A: It uses complex organs (eyes) and specialized photoreceptors.
Tactile (Touch) Receptors
Q: What are free nerve endings?
A: Unencapsulated receptors detecting pain, temperature, and light touch.
Q: What do Merkel discs detect?
A: Steady pressure and texture (tonic receptor).
Q: What do Meissner corpuscles detect?
A: Light touch and texture; found in dermal papillae(Phasic)
Q: What do Pacinian (lamellated) corpuscles detect?
A: Deep pressure and vibration (phasic).
Q: What do Ruffini endings detect?
A: Skin stretch and sustained pressure (tonic).
Q: Application: Which receptor alerts you when a bug crawls on your arm?
A: Hair root plexus / hair receptor.
Q: What structures make up the integumentary system?
A: The skin (epidermis + dermis), hypodermis, hair, nails, and glands.
Q: What are the major functions of the skin?
A: Protection, sensory detection, thermoregulation, vitamin D synthesis, waterproofing, immune defense.
Q: Application: Why does sweating cool the body?
A: Evaporation removes heat; vasodilation increases heat loss.
Q: What tissue makes the epidermis?
A: Stratified squamous keratinized epithelium.
Q: What is the main cell type in the epidermis?
A: Keratinocytes.
Layers of the Epidermis(Deep → Superficial)
Stratum basale →
stem cells, melanocytes, Merkel cells
Stratum spinosum →
keratinocytes + Langerhans cells
Stratum granulosum →
keratin + waterproofing
Stratum lucidum →
only in thick skin (palms, soles)
Stratum corneum →
dead keratinized cells (protection)
Q: Application: Which layer is responsible for fingerprints?
A: Dermal papillae of the papillary layer pressing into epidermis.
Q: Application: Which layer would blister first after a burn?
A: The epidermis (particularly stratum spinosum + granulosum).
Q: How long does it take for a keratinocyte to move from stratum basale to flaking off the surface?
A: 30-40 days.
Thin vs. Thick Skin
Q: Where is thick skin found?
A: Palms and soles.
Q: Which layer is present only in thick skin?
A: Stratum lucidum.
Q: What are the two layers of the dermis?
A: Papillary layer (areolar CT) and reticular layer (dense irregular CT).
Q: What receptors are found in the papillary layer?
A: Meissner corpuscles, temperature receptors, pain receptors.
Q: What receptors are found in the reticular layer?
A: Pacinian corpuscles.
Q: What is the hypodermis made of?
A: Areolar and adipose tissue.
Q: What is the hypodermis functions?
A: Insulation, energy storage, cushioning, thermoregulation.
Q: Application: Why are subcutaneous injections effective?
A: High vascularity allows slow absorption into bloodstream.
Q: What are the functions of hair?
A: Protection, sensation (hair receptors), and heat retention.
Q: What is the hair bulb?
A: The base of the hair follicle where growth occurs (contains hair matrix).
Q: What detects hair movement?
A: Hair root plexus (hair receptor).
Q: What are nails made of?
A: Hard keratin.
Q: What is the function of nails?
A: Protection and improving fine touch.
Q: What do sebaceous glands produce?
A: Sebum (lubricates skin/hair).
Q: Where are sebaceous glands NOT found?
A: Palms and soles.
Q: What do eccrine sweat glands do?
A: Thermoregulation through watery sweat.
Q: What do apocrine sweat glands do? A: Produce thicker sweat in axilla/groin (scent).
Q: Application: Why aren't your palms oily?
A: They lack sebaceous glands.
Q: Where are taste buds located?
A: Mostly on papillae of the tongue (fungiform, foliate, circumvallate), but also on the soft palate, epiglottis, and pharynx.
Q: What is the structure of a taste bud?
A: A cluster of gustatory cells, supporting cells, and basal stem cells.
Q: What are gustatory receptor cells?
A: Specialized epithelial cells with microvilli that detect dissolved chemicals (tastants).
Q: What stimulates gustatory cells?
A: Tastants that bind to receptors on the microvilli.
Q: What are the primary taste sensations?
A: Sweet, sour, salty, bitter, umami.
Q: Which taste indicates potential toxins?
A: Bitter.
Q: Which taste detects amino acids/proteins?
A: Umami (glutamate).
Q: Which cranial nerves carry taste information?
A: CN VII (facial), CN IX (glossopharyngeal), CN X (vagus).
Q: Where does taste travel after cranial nerves?
A: Medulla → Thalamus → Primary gustatory cortex.
Q: Application: If someone loses taste on the anterior 2/3 of their tongue, which nerve is damaged? A: CN VII (facial nerve).
⭐ M12.1 — OLFACTION (Smell)
Olfactory Anatomy
Q: Where are olfactory receptors located?
A: In the olfactory epithelium of the superior nasal cavity.
OLFACT
Q: What is the olfactory epithelium composed of?
A: Olfactory receptor cells, supporting cells, and basal stem cells.
Q: What are olfactory hairs?
A: Cilia on olfactory neurons where odorants bind.
Q: How do odorants activate receptors?
A: Odorant molecules dissolve in mucus and bind to receptors, triggering an action potential.
OLFACT
Q: Why does smell trigger strong memories?
A: Olfactory pathways go directly to the limbic system (emotion/memory).
Q: What is the path of smell signals?
A: Olfactory receptors → Olfactory nerves → Olfactory bulb → Olfactory tract → Brain (including limbic system).
OLFACT
Q: Application: Why might COVID-19 temporarily affect smell?
A: Damage to olfactory epithelium disrupts receptor function.
⭐ M12.2 — Gross Anatomy of the Eye
Tunics of the Eye
Q: What are the three tunics of the eye?
A: Fibrous tunic, vascular tunic, neural tunic.
Q: Components of the fibrous tunic?
A: Cornea + sclera.
Q: Components of the vascular tunic? A: Iris, ciliary body, choroid.
Q: Components of the neural tunic?
A: Retina (pigmented layer + neural layer).
Q: What structures refract light?
A: Cornea (major refraction), lens (fine adjustment), aqueous humor, vitreous humor.
Q: What adjusts the shape of the lens? A: Ciliary muscle + suspensory ligaments.
Q: Application: Why does the lens become rounder when you look at something close?
A: Ciliary muscles contract → ligaments loosen → lens rounds.