Chapter 14 - Nervous System Functions Flashcards
What is sensation?
Concious awareness of the effects of stimuli, received by sensory receptors. The brain perceives info about body and environment via senses.
What are the steps to sensation?
- Stimuli originates either inside or outside the body. And is detected by the sensory receptors.
- Stimuli is converted into action potentials which are carried to the CNS.
- Within the CNS nerve tracts convey action potentials to the cerebral cortex and other areas of CNS.
What are general senses and what are they?
They are distrubuted over large parts of the body. These general senses are somatic (info about body and environment) examples are touch, pressure, temp, pain. And Visceral primarily pain and pressure in the internal organs.
What are special senes and what are they?
They are found in special locations within the body and have specialized nerve endings. They include sight, smell, taste, hearing and balance.
What are the 5 types of sensory receptors according to the categorized by the type of stimulus?
Mechanoreceptors: Respond to manual stimulus tickle, touch, vibration.
Chemoreceptors: Respond to different chemicals. Smell and taste.
Thermoreceptors: Respond to change in temperature.
Photoreceptors: Respond to light. Sense of vision.
Nociceptors (pain receptors): Extreme mechanical, chemical or thermal stimuli. Causes sense of pain.
What are the 3 types of receptors catergorized by location?
Exteroreceptors: Associated with skin
Visceroreceptors: associated with organs.
Proprioceptors: Associated with joints and tendons.
Describe Free Nerve Endings
Simplest and most common sensory receptor
Scattered through body
Include: cold and warm receptors, pain receptors
What are merkel cells?
More complex than free nerve endings.
Located in basal layer of epidermis.
Responds to light touch and superficial pressure.
What are hair follicle receptors?
Respond to slight bending of hair.
Wraps around the hair follicle.
What are Pacinian Corpuscles?
Complex receptors, resembling an onion.
Located in deep dermis or hypodermis.
Detects deep cutaneous pressure + vibration
What is meissner corpsucles?
Detect fine touch (two-point discrimination)
Located in the dermal papilla.
What is the Ruffini End Organ?
Responds to continuous touch or pressure
Found in dermis, mostly fingers.
What are muscle spindles?
Provides information about length of muscles.
Involved in stretch reflex.
What is the difference between primary receptors and secondary receptors?
Primary Receptors: Transmit action potentials toward the central nervous system.
Secondary Receptors: release neuro-transmitters and form action potential.
What is adaption/accomodation?
Decresed sensitivity due to a continued stimulus
What are the types of Adaption Receptors?
Tonic receptors: slowly adapting receptors; accommodate very slowly.
Phasic receptors: rapidly adapting receptors; accommodate rapidly.