Chapter 50: Sensory and Motor Mechanisms Flashcards
Mechanoreceptor
a type of sensory receptor which relays extracellular stimulus to intracellular signal transduction through mechanically gated ion channels (i.e. touch, pressure, stretching, sound waves, and motion)
Hearing process is called…
Auditory transduction
Oval window
membrane-covered opening from the middle ear to the cochlea of the inner ear
Round window
a membrane covering the entrance to the cochlea in the inner ear
hair cells
sensory cells with hair like projections that detect motion
Cochlea
the spiral cavity of the inner ear containing the organ of Corti, which produces nerve impulses in response to sound vibrations; diameter is not the same throughout
Equillibrium
(type of mechanoreceptor) pertains to the condition of achieving balanced thereby resulting in a stable system
statocyst
a small organ of balance and orientation in some aquatic invertebrates, consisting of a sensory vesicle or cell containing statoliths
Semicircular canals
three tiny, fluid-filled tubes in your inner ear that help you keep your balance; perceive rotational movement
utricle and saccule
perceive linear acceleration
Mammalian middle ear converts…
Air pressure waves to fluid pressure waves
What causes dizziness?
Moving fluid in the semicircular canals encounters a stationary cupula
Electromagnetic receptor example
photoreceptors
photoreceptors
sensory cells that contain light-absorbing pigment molecules
rods
grayscale detection, night vision, located at edges of retina, shared ganglia
cones
different colors, fine detail, less numerous than rods, individual ganglia
Light reaction
Light alters retinal from cis to trans isomer closing Na+ channels
Glutamate
the neurotransmitter of the neurons of the vertical pathways through the retina
Amacrine cells
Interneurons in the retina
Chemoreceptors
receptors that sense solute concentration (ex: smell and taste)
Smell process
- Odorants bind with chemoreceptor on membranes of olfactory cilia
- Cyclic AMP opens channels permeable to Na & Ca
Taste buds
Epithelial cells - not neural cells
Taste process
Chemical dissolved in saliva will bind with certain receptors
Number of smell receptors vs number of taste receptors
400 vs 5
Connection between taste and smell
Independent systems that work together to communicate to the brain; about 75% of taste comes through our nose
Thermoreceptors
Receptors beneath epidermis where protein next to ion channel responds to temperature change; expansion of protein causes ion channel to close; exist in large quantities
Muscle structure
Neurons connect 1 to many fibers
Muscle fibers are made up of…
Myofibrils
Myofibrils are made up of…
Sarcomeres
Sarcomere
The contractile unit; thick filaments of myosin and thin units of actin
Process of muscle contraction
- Neurotransmitter starts action potential at muscle fiber
- Action potential travels down T tubules
- Myosin binds to sites on actin filaments
- Myosin heads bind to actin, then bend during “power stroke”
- Myosin releases from actin
Cycle of muscle contraction continues as long as what is present?
Calcium
Visual information is integrated where?
the retina and the visual cortex
Calcium’s role in muscle contraction
bind with troponin, changing its shape so that the myosin binding sites on actin are exposed
