L4 taste, smell, touch Flashcards
What does the frontal lobe do?
Reward, attention, memory, planning, and motivation
What does the parietal lobe do?
Sense of touch, temperature, pain and language processing
What does the temporal lobe do?
Memory, hearing, language, comprehension, emotion
What does the occipital lobe do?
Visual processing
Retinotopic map is for _____ input.
visual
Tonotopic map is for _____ input
audio
3 cortices with sensory modalities.
Somatosensory, gustatory (taste), olfactory (smell)
Brain stem contains… (3)
Midbrain, pons and medulla
Brainstem provides the main motor and sensory innervation to the face and neck via ________
cranial nerves
Of 12 pairs of cranial nerves, ___ pairs come from the brain stem.
10
What role does the brainstem play?
Regulation of cardiac and respiratory function
Where does spinal cord attach to?
Brainstem
Name the conduit of information (brain-body)
Skin, joints, muscles. spinal nerves: dorsal root, ventral root
What is peripheral nervous system (PNS)?
Nervous system outside the brain and spinal cord
What does somatic PNS innervate?
Skin, joints, muscles
What is dorsal root ganglia?
Clusters of neuronal cell bodies outside the spinal cord that contain somatic sensory axons
What does visceral PNS do?
Innervates internal organs and their functions such as blood circulation, hormone release, heart rate, digestion and urination, sexual arousal
What is phrenology based on?
The concept of brain is the organ of the mind, and that certain brain areas have localized specific modules
Franz Joseph Gall’s assumption in 1796, that _________, _________, and _______ are located in a specific parts of the brain is considered an important historical advance toward neuropsy.
Character, thought, emotions
Brain map is continuously modified by ______
experience
What happens to a violinist’ brain map?
Auditory cortex will have larger sensitivity to violin. Somatosensory cortex will enlarge cortical map to left-hand fingers
What is perception?
Continuous interpretation of the world based on sensory systems, memory, and other neural processes
Information is sent from the periphery to ____
CNS
External environment _______ ; internal environment ________
sensory; visceral afferent
What does somatosensory system sense?
Pressure and temperature
What is somatic?
sensations of skin
What is proprioception?
perception of limb and body
What is the modality of balance and equilibrium?
Acceleration
What is the modality of taste and smell?
Chemicals
What do sensory receptors do?
Detect specific form of energy in the external environment
Photoreceptors are for? and its modality.
Vision; photons of light
Chemoreceptors are for? and its modality.
Taste, smell, pain; chemicals dissolved in saliva, chemical dissolved in mucus, chemicals in extracellular fluid
Thermoreceptors are for? and its modality.
Warmth and cold; increase T between 30-43, decrease in T between 35-20
Mechanoreceptors are for? and its modality.
Vibration, sound, balance and equilibrium; pressure, sound waves, acceleration
Name 2 mechanoreceptors.
Pacinian corpuscle, hair cells
What is sensory transduction?
Conversion of stimulus energy into electrical energy
Receptor/ graded potentials are triggered by _____.
sensory stimuli
If the receptor potential __________, it can generate an action potential.
exceeds threshold
__________ in spinal cord. (somatosensory)
Dorsal root ganglion
_________ in nasal cavity. (smelling)
Olfactory receptor cells
__________ in cochlear. (hearing)
Hair cells
_______ in retina. (vision)
Rod/cone cells
_________ in taste bud. (taste)
Taste receptor cell
What is sensory pathways?
Specific neural pathways transmitting information of a specific modality
Sensory unit: all receptors are of _______ type within a _______
similar; modality
Sensory unit: __________ may result from activation of receptors
Action potential
What is receptive field?
Area in which a sensory unit is activated
What is the coding for stimulus intensity?
Frequency of action potentials; number of receptors or units activated (population coding)
Stronger stimulus activates more _____ or more _______
receptors; sensory units
Name the generalized pathway for sensory systems.
Stimulus -> receptors -> afferent neuron -> spinal cord/ brainstem -> second-order neuron -> thalamus -> third-order neuron -> cortex
Somatosensory receptors: What does proprioceptors do?
Position of the limb in space (joint angle, muscle length, muscle tension)
Somatosensory receptors: What does mechanoreceptors do?
Sensation of mechanical pressure/ distortion
Somatosensory receptors: What does thermoreceptors do?
Sensation of relative changes in temperature in Ruffini’s ending
Somatosensory receptors: What does nociceptors do?
Pain sensation by damaging stimuli in free nerve ending
Name the dorsal column-medial lemniscal pathway
Proprioceptors/ mechanoreceptors -> medulla oblongata -> thalamus -> primary somatosensory cortex
What are the somesthetic sensation?
Touch & pressure, proprioception
Name the spinal cord-thalamus pathway
Nociceptors/ thermoreceptors -> spinal cord -> thalamus -> primary somatosensory cortex
What does the spinothalamic tract sense?
Temperature and tissue-damaging stimuli
Which pathway skipped medulla?
Spino cord-thalamus pathway
Pain sensation is produced by _________
tissue-damaging stimulus
Pain elicits ________ and ________ response.
autonomic; emotional
Pain perception in spinothalamic tract.
Somatic PNS, visceral PNS -> thalamus
What is two-point discrimination?
A sensory acuity that is an ability to perceive 2 points on the skin
Two-point discrimination is used to determine _____
tactile agnosia
What is two-point threshold?
The smallest distance between two points that still results in the perception of two distinct stimuli is recorded as the two-point threshold
What is tactile acuity?
The keenness or sharpness of the sense of touch, usually measured by the two-point threshold
Which place has the highest acuity?
Lips
Which place has the least acuity?
Calf
What is a taste bud?
A cluster of taste cells (receptor cells)
Microvilli at the _____ of the taste cells extend into the ______
apical end; taste pore
How many taste buds?
More than 10,000 taste buds
Taste pore exposed to ____ in mouth.
saliva
How many taste receptors cells per taste bud?
50-150
Taste receptors respond to ______, that give food its flavor.
tastants
Taste sour due to…
H+
Taste salty due to…
Na+
Taste sweet due to…
ligands (sugar)
Taste bitter due to…
ligands (quinine)
Do each taste receptor cell only respond to one taste?
No, each responds to all four primary tastes. Receptor cells generally respond to one taste more strongly than the others
One taste bud one receptor cell?
Different types of receptor cells located within a taste bud
Sensory neurons = cranial nerves…
VII, IX and X
Neural pathway for taste terminate in _______
brainstem gustatory nucleus -> thalamus -> gustatory cortex in parietal lobe
Olfaction depends on chemicals in ____ that bind to ________ in the ________.
air; chemoreceptors; olfactory epithelium
Where does olfactory epithelium locate?
In nasal cavity
What are the 3 cell types that make olfactory epithelium?
Receptor cells; basal cells; sustentacular cell
Describe the receptor cells for smell.
Neurons that respond to odorants
What is basal cells?
Precursor cells for new receptor cells
What does sustentacular cell do?
Maintain extracellular environment
Name the order in olfactory epithelium.
Mucus layer -> cilia of receptor cell -> receptor cell -> sustentacular cell -> basal cell -> lamina propria -> cribriform plate -> axon of olfactory nerve
The neurons (basal neurons) that are _______ continuously.
replaced
Chemoreceptors will be used when cilia project into _____.
mucus
Where do olfactory binding proteins locate?
Mucus
What do olfactory binding proteins do?
Transport odorants to receptors
_______ comprises cranial nerve I, the _______ nerve.
Axons of receptor cells; olfactory
Neural pathway for olfaction: Communication between _______ and _______ in glomeruli.
Mitral cells; olfactory neuron
Neural pathway for olfaction: Relay in _______ to _______ cortex
olfactory tubercle; cerebral
The neocortex is reached only by a pathway that synapses in the ______ of the _____
medial dorsal nucleus; thalamus
