Practical #3 - Sensory Stuff

Question 1

What are the 5 types of receptors?

Answer 1

• Chemoreceptors
• Pain Receptors (nociceptors)
• Photoreceptors
• Mechanoreceptors
• Thermoreceptors

Question 2

What do chemoreceptros receive?

Answer 2

• respond to changes in the chemical concentrations of body fluids, ingested materials and the outside encironment

Question 3

WHat do Pain receptors respond to?

Answer 3

• respond to tissue damage from a variety of causes

Question 4

What do thermoreceptors respond to?

Answer 4

• respond to changes in the external or internal temperatures

Question 5

What do Photoreceptors respong to?

Answer 5

• respond to the presence of and changes in electromagnetic radiation, particularly in the visible light portion of the spectrum

Question 6

What do mecanoreceptors respond to?

Answer 6

• 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

Question 7

What is a sensation?

Answer 7

• also called a perception
• occurs when the brain receives information from sensory cells and interprets them

Question 8

What is the difference between sense organs and effector organs?

Answer 8

• Sense organs - send signals from the receptors to the central nervous system
• Effector organs - elicit some response to the stimulus
  
  • muscles and glands

Question 9

How does a blind spot occur?

Answer 9

• There are no photoreceptors over the point at which the optic nerve leaves the back of the eye

Question 10

What are the 2 groups of sensory cells in the retina? What are their functions?

Answer 10

• 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

Question 11

What is the near point?

Answer 11

The shortest distance that an object isin shapr focus

Question 12

How is the skin and organ system?

Answer 12

• It is the integumentary system
• includes the epidermis and dermis and accessory structures
• numerous exocrine glands
• Sensory structures

Question 13

What are the main functions of the integumentary system that maintain homeostasis?

Answer 13

• 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!

Question 14

What are the 2 major layers of skin…and then the 4-5 “subclass” layers of skin

Answer 14

• 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

Question 15

Where do Melanocytes originate from and what do they do?

Answer 15

• 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

Question 16

How is the Dermis composed?

Answer 16

• 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

Question 17

What are the 3 main mechanoreceptors found in the dermis?

Answer 17

• 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

Question 18

What other glands/and thing can you find in the skin?

Answer 18

• Hair follicles and their muscles
  
  • arrector pili muscles
  • root hair plexus
  • Sebaceous glands
• Sweat glands

Question 19

Describe the make-up of the tongue

Answer 19

• 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

Question 20

What are the 6 known taste sensations?

Answer 20

• Salty
• Sweet
• Sour
• Bitter
• umami
• water