chapter 50: sensory and motor mechanisms Flashcards
What are the four basic functions in sensory pathways?
- sensory reception
- transduction
- transmission
- integration
What is the role of sensory reception?
- sensations begin with sensory reception, detection of stimuli by sensory receptors
- there are neuronal receptors: afferent neuron
- there are non-neuronal receptors: receptor regulates afferent neuron
What is the role of sensory transduction?
- its the conversion of stimulus energy into change in sensory receptor membrane potential.
- the change in membrane potential is called receptor potential
What is the role of transmission?
- transducing the energy in a stimulus into a receptor potential initiates transmission of action potentials
- sensory neurons produce action potentials
- if receptor is a neuron, larger receptor potential results in more frequent action potentials.
- if receptor isnt a neuron, larger receptor potential causes more neurotransmitters to be released
What is the perception?
brains construction of stimuli
the brain distinguishes stimuli from different receptors based on the are in the brain where action potential arrives
What is amplification?
strengthing of a sensory signal during transduction
What is sensory adaptation?
decrease in responsiveness to continued stimulation
What are the different kinds of sensory receptors?
- mechanoreceptors
- chemoreceptors
- electromagnetic receptors
- thermoreceptors
- pain receptors
What are mechanoreceptors?
- they sense physical deformation caused by forms of mechanical energy
- responses to touch, stretch, motion, pressure and sound relies on mechanoreceptors
- found in the dendrites
What are chemoreceptors?
-transmit information about the total solute concentration of a solution
- when stimulus molecule binds to chemoreceptor, it becomes more or less permeable to ions
What are electromagnetic receptors?
- detect electromagnetic energy such as light, electricty and magnetism
- animals use this to migrate using earths magnetic field
What are thermoreceptors?
- respond to heat or cold and help regulate temperature by signalling both surface and body core temperatures
- some snakes use this to detect infrared radiation emitted by warm prey
What are pain receptors?
- pain receptors or nociceptors detect stimuli that reflect harmful conditions
- they respond to excess heat, pressure, chemicals
Why are mechanoreceptors responsible for hearing and equilibirum?
- mechanoreceptors located in organs called statocysts, where they detect movement of granules called statoliths
- some arthropods sense sounds with body haurs that vibrate
What is the cochlea?
has two large structure found in the ear
What is the organ of corti?
it contains the mechanoreceptors of the ear
How do we hear?
- vibration creates percussion waves int he air
- three bones in ear transmit vibrations to oval window
- vibrations create pressure waves in fluid in cochlea that travel through vestibular canal
- causes basilar membrane to vibrates, bending its hair cells
- this depolarizes membranes of mechanoreceptors and sends action potential to the brain via auditory nerve
- fluid waves dissipates when they strike the round window at the end of the tympanic canal
- volume is amplitude and pitch is frequency of sound wave
How do we maintain equilibrium?
- the utricle and saccule contain granules called otoliths
- three semicircular canals contain fluid and can detect anglular movement
How do fish stay in equilibrium?
they have a lateral line system, containing mechanoreceptors that detect and respond to water movement.
What organs are used to detect light?
- planarians: ocelli
- Insects: compound eyes: several thousand light detectors
- spiders: single-lens eyes (iris changes diameter of pupil to control amount of light
What causes us to see color?
we have three types of cones with different pigments, red, green or blue. the pigments are photopsins and are formed when retinal binds to three distinct opsin proteins.
How do we focus?
by changing the shape of the lens
What is gustation dependent on?
detection of tastant chemicals
What is olfaction dependent on?
dependent on the detection of odorent molecules
What are thin filaments composed of?
two strands of actin coiled around one and another
What are thick filaments composed of?
staggered arrays of myosin molecules
What is the vertebrate skeletal muscle made of and whats its purpose?
moves bones and the body
consists of a bundle of long fibers running parallel to length of the muscle
each muscle fiber is itself a bundle of smaller myofibrils
What is another name for the vertebrate skeletal muscle and why?
striated muscle, becauase it has regular arrangement of myofilaments
What is the functional unit of a muscle called?
sarcomere
What is the sliding filament model?
thin and thick filaments slide past each other longitudinally, powered by myosin molecules
How does the muscle contract?
- head of myosin molecule binds to an actin filament
- this pulls the thin filament toward the center of sacromere
- muscle contraction requires repeated cycles of binding and release
- glycolysis and aerobic respiration generate ATP needed to sustain muscle contraction
What does the skeletal system provide?
provides rigid structure to which muscles attach
functions in support, protection and movement
What are the three different types of skeletal systems?
- hydrostatic skeleton (lack hard parts)
- exoskeleton (external hard parts)
- endoskeleton (internal hard parts)
What does a hydrostatic skeleton consist of?
fluid held under pressure in a closed body compartment
used for peristalsis
What do endoskeletons consist of?
hard internal skeleton buried in soft tissue
What are the three types of joints found in the skeleton?
- ball and socket
- hinge joint
- pivot joint
