Practical #3 - Sensory Stuff Flashcards
What are the 5 types of receptors?
- Chemoreceptors
- Pain Receptors (nociceptors)
- Photoreceptors
- Mechanoreceptors
- Thermoreceptors
What do chemoreceptros receive?
- respond to changes in the chemical concentrations of body fluids, ingested materials and the outside encironment
WHat do Pain receptors respond to?
- respond to tissue damage from a variety of causes
What do thermoreceptors respond to?
- respond to changes in the external or internal temperatures
What do Photoreceptors respong to?
- respond to the presence of and changes in electromagnetic radiation, particularly in the visible light portion of the spectrum
What do mecanoreceptors respond to?
- respond to the changes in touch and pressure.
- Sense mechanical forces that deform or displace tissues/organs in the body.
- May be neurons, but are often specialized epithelial cells
What is a sensation?
- also called a perception
- occurs when the brain receives information from sensory cells and interprets them
What is the difference between sense organs and effector organs?
- Sense organs - send signals from the receptors to the central nervous system
-
Effector organs - elicit some response to the stimulus
- muscles and glands
How does a blind spot occur?
- There are no photoreceptors over the point at which the optic nerve leaves the back of the eye
What are the 2 groups of sensory cells in the retina? What are their functions?
-
Rods
- sensitive to light
- Perceives white light when stimulated
- Much more prevalent in the peripheral
-
Cones
- Predominate in the area of the fovea
- Responsible for shapr color vision in daylight
What is the near point?
The shortest distance that an object isin shapr focus
How is the skin and organ system?
- It is the integumentary system
- includes the epidermis and dermis and accessory structures
- numerous exocrine glands
- Sensory structures
What are the main functions of the integumentary system that maintain homeostasis?
- Involved in respiration
- Excretion of nitrogenous wastes
- water and salt balance
- Vitamin D3 is produced here (in humans)
- stores water/salts/fats
- supports and protects the body from microbial infections
- protects against physical abrasion
- temperature regulation
- sensory reception!
What are the 2 major layers of skin…and then the 4-5 “subclass” layers of skin
- Epidermis
- Dermis
-
Startum Corneum
- surface layer of dead keratinocytes. Cells continually flake off
-
Stratum Lucidum
- Clear, dead skin layer on palms and feet
-
Stratum Granulosum
- living cells that helps water proof the skin
-
Stratum Spinosum
- living cells, keratin helps hold these together
-
Stratum Basale
- lowest level, attaches to basement membrane
- undergo mitosis and daught cells move up through the layers
Where do Melanocytes originate from and what do they do?
-
Melanocytes
- located in the deepest layer of epidermis
- Manufacture melanin which is transferred to keratinocytes inside melanosomes (vesicles)
- melanin - helps protect deeper tissues from UV radiation
How is the Dermis composed?
- Located under the epidermis
- composed of several types of connective tissues, whose collagen fibers give skin elasticity and tensile strength
-
papillary layer
- outer layer of dermis, composed of areolar CT
-
Reticular layer
- inner layer of dermis, composed of dense CT - collagen and fibers
-
papillary layer
What are the 3 main mechanoreceptors found in the dermis?
-
Tactile (Meissner’s) Corpuscles
- small sense organs beneath the epidermis
- respond to light touch and adapt rapidly
-
Pacinian Corpuscles
- deeper in dermis (reticulated layer) detect stronger pressure changes and expecially to vibration of the skin.
- adapt rapidly
-
Merkel Cells
- Located in the stratum basale
- have contact with nerve fibers
- sense fine contatct with the skin
What other glands/and thing can you find in the skin?
- Hair follicles and their muscles
- arrector pili muscles
- root hair plexus
- Sebaceous glands
- Sweat glands
Describe the make-up of the tongue
- Taste receptors on the tongue
- There are 40 sensory neurons (gustatory receptors) located in each of the 3,000 taset buds
- Taste buds are located on the papillae of our tongue
- These are chemoreceptors
- 3 cranial nerves send taste sensations to the brain
- facial, glossopharyngeal and vagus nerves
What are the 6 known taste sensations?
- Salty
- Sweet
- Sour
- Bitter
- umami
- water
