biopysch exam 2 Flashcards
Ligament
They hold the lens in place and are connected to the ciliary muscles on the top and bottom
Iris
A thin layer behind the cornea
Pupil
The hole at the center of the iris
Size is regulated by iris
Size is a compromise between sensitivity and acuity
Lens
A circular layer behind the iris
Focus light on the retina
Focus is called accommodation
When focused on something near lens is cylindrical
When focused on something far away lens in flattened
Cornea
The outermost surface of the eye in front is clear and dome-shaped
Sclera
The outermost surface of the eye, excluding the cornea, is the white of the eye
Retina
The part of the eye beyond the lens
Optic nerve
They line the retina at the top and bottom and leave together at the back of the eye
Blind spot
The spot where the optic nerve leaves through the back of the eye
Order light passes through the eye
Cornea, pupil, lens, retina
Where is the fovea located, and what is its function
The fovea is an indentation about .33 cm in diameter at the center of the retina
It is the area of the retina that is specialized for high acuity vision
The thinning of the retinal ganglion cell layer at the fovea reduces the distortion of incoming light
What is the optic nerve composed of, and why does it create a blind spot for each eye
They line the retina at the top and bottom and leave together at the back of the eye
The spot where the optic nerve leaves through the back of the eye and its composed of axons of retinal ganglion cells
lacks photoreceptors
Purkinje effect
The difference in the photopic and scotopic spectral sensitivity and interesting visual effect can be observed during the transition from photopic to scotopic visions
In dim light conditions, which portions of the spectrum appear brighter than equally intense light in the red portion of the spectrum
Blue and purple portions of the spectrum
Electrical pulses induced by sound first travel to the hindbrain before interacting with the thalamus that relays the signals to the primary auditory cortex
The nuclei of the thalamus that send fibers where to the inprimary auditory cortex
Fibers ascend to the medial geniculate nucleus of the thalamus
Free nerve endings
Cutaneous receptor
Provide signals about pain and temperature
Painian corpuscles
Cutaneous receptor
Deep, fast-adapting touch receptors
Merkel receptors
Cutaneous receptor
Slow adapting touch receptors
Ruffini corpuscles
Cutaneous receptor
Slow adapting touch receptors
How is the cingulate cortex involved in the perception of pain
Using PET, researchers have found that the anterior cingulate cortex has been consistently implicated in the cortical perception of pain
However, it appears that this activation is more related to emotional responses to pain rather than the perception of pain
Why might the thermal grid illusion only activate the cingulate cortex
It plays a critical role in processing pain perception particularly in integrating sensory information related to temperature and interpreting it as a potentially harmful stimulus, even when the actual physical sensation isn’t painful
This is why it shows significant activation even when the illusion creates a burning sensation despite not experiencing true heat damage
The periaqueductal gray (PAG) is descending analgesia circuit
What is the effect on pain when the PAGis stimulated
Reduction in perceived pain as it activates the body’s natural pain inhibiting mechanisms
Which of the gustatory systems activate metabotropic receptors
1 umami, 2 sweet, 25 bitter
Which of the gustatory systems activate ionotropic receptors
Salty and sour
In most somatosensory systems, which areas of the neocortex receive input directly from thalamic relay nuclei
The primary sensory cortex
Do the relay nuclei project to primary secondary or association cortex
Primary sensory cortex
What are the 3 principles of sensorimotor function
Hierarchically organized
Motor output is guided by sensory input
After much practice, lower levels of the organization perform well-learned tasks with little higher involvement***automaticity
What is the role of the posterior parietal association cortex in sensory motor function
receives input from visual, auditory, and somatosensory systems
How does the hierarchical nature of the somatosensory system differ from the hierarchical nature of the sensorimotor system
The direction of information flow
Somatosensory flows upward
Sensorimotor flows downward
Why is receiving input from the various somatosensory systems important to the initiation of movement
informs us about objects in our external environment through touch and about the position and movement of our body parts (proprioception) through the stimulation of muscle and joints. also monitor the body’s temperature, external objects, and environment, and provide information about painful, itchy, and tickling stimuli. The sensory information processed by the somatosensory systems travels along different anatomical pathways depending on the information carried.
Lesions to this part of the brain can result in contralateral neglect (Mrs.S, the woman who turned in circles)
Produced by very large right parietal lesions
Individuals only attend to the right side of the body or item in the environment
Premotor cortex supplementary motor areas and cingulate motor areas can be found in which hierarchical area of motor cortex
Second motor area
Two areas of the premotor cortex
Three supplementary motor areas
Three cingulate motor areas
What are mirror neurons?
When do they fire
Fire when an individual makes foal direct movements
Fire when an individual observed someone else performing goal directed movements
It may be a mechanism for social cognition
Stereognosis
The ability to identify only by touch
Astereognosis
Loss of ability to identify by touch
The cerebellum integrates and coordinates activity in the sensorimotor system and contains over half of the brain’s neurons
How much of the brain’s total mass does the cerebellum contribute
Only 10 percent of the brain’s mass, but it contains over half of the brain’s neurons
Signals sent from the primary motor cortex to the motor neurons of the spinal cord are conducted over 4 different pathways
2 in the dorsolateral corticospinal tract
2 in the ventromedial corticospinal tract
Which tract projects to the distal limb muscles
Dorsolateral controls motor neurons of distals muscles
which tract projects to the trunk and proximal limb muscles
Ventromedial controls the neurons of the proximal muscles
Lawrence and Kuypers’ experiments involving transactions of the dorsolateral and ventromedial corticospinal tract
What effect did this have on the monkeys
Impacted posterior and balance
isometric muscle contractions
One where muscle tension increases, but muscles do not shorten, and there is no action at the joint
Plank
dynamic muscle contractions
One where muscles shorten to produce action at a joint
Bicep curl
Which one produces action at a joint
Dynamic
Totipotent cells
The three embryonic stem cells crucial for neurodevelopment
Cells can develop into any class of cells in the body
Pluripotent cells
The three embryonic stem cells crucial for neurodevelopment
Cells can develop into many but not all classes of body cells
Multipotent cells
The three embryonic stem cells crucial for neurodevelopment
Cells can develop into different cells of only one class
Different kinds of blood cells
5 phases of neurodevelopment
Induction of the neural plate
Neural proliferation
Migration and aggregation
Axon growth and synapse formation
Neuron death and synapse rearrangement
What does the neural plate develop into
develops about three weeks after conception and becomes the neural tube
What does the neural groove develop into
Formed through the folding of the neural plate, the lips of the neural groove fuse it from the neural tube
Which part of the neural tube eventually becomes the cerebral ventricles and spinal cord
The posterior part becomes the spinal cord
The anterior part becomes the cerebral ventricles
Developing neurons must proliferate, migrate, and aggregate
What role do cell adhesion molecules (CAMS) play in the process of aggregation
There are 3 mechanisms involved in aggregation
Mediated by cell adhesion molecules
CAMS are found on the surfaces of neurons and other cells
CAMS can recognize molecules on other cells and adhere to them
Aggregation
Occurs when cells have migrated to the same area to form the structures of the nervous system
Growth cone
After migration is complete, neurons grow axons and dendrites
Accurate localization is due to growth cones
Amoebalike structure at the growing tip of axons and dendrites
Necrosis
Cells break apart, spilling the contents into the extracellular fluid, which may cause inflammation
Apoptosis
Active cell death
The internal cell structures are cleaved and packed in membranes before the cell breaks apart
Up to 50% of neurons that develop die during normal development
Which is safer
Which results in inflammation
Apoptosis
Necrosis
Which part of the brain reaches full maturity last
The prefrontal cortex is the last to mature, around 25 years
What are perseverative errors
Damage to the prefrontal cortex leads to perseverative errors
Behavior can look like an infants
How are these indicative of an immature prefrontal cortex
Piaget’s experiment in 7-12 month olds
A small toy was shown to an infant, then as the child watched, it was placed behind one of two screens after a delay, the infant was allowed to reach for the toy
7 months later, they reached for the screen behind it and had seen the toy place
However, if the place was changed after several trials of the same location then they would reach behind the old screen rather than where the toy was now located
Even though they saw the movie happen, it is indicative of perseverative error
Critical periods
when experience must occur at a specific time
Sensitive periods
when experience has an effect outside of the specific time or interval
In which does the vast majority of experiential effects on neurodevelopment occur
During early childhood, the brain is sensitive to environmental stimuli, with critical periods for different functions like language acquisition and social development
In which part of the human brain does most neurogenesis occur
The hippocampus, specifically in the subgranular zone SGZ of the dentate gyrus, is where new neurons are primarily generated throughout adulthood
What are the 2 core symptoms of autism spectrum disorder (ASD)
Social communication difficulties and repetitive behaviors
What are brain tumors
A group of cells growing independently of the rest of the body
Benign
Low spread risk
Encapsulated growth within its own membrane is
Malignant
High spread risk
Infiltrating grow diffusely through surrounding tissue
Which types of tumors are most likely to be benign
Which types are most likely to be malignant
benign: lipoma a tumor made up of fat cells
malignant: carinoma (breast, colon, prostate, and lung cancers)
What is meant by encapsulated tumors and infiltrating tumors
encapsulated: a tumor that is surrounded by a layer of connective tissue called a capsule
infiltrating: a type of cancer that has spread beyond its original location and into surrounding tissues
Cerebral hemorrhage
Strokes can result from cerebral hemorrhage or cerebral ischemia
Blood leaks into the brain
Cerebral ischemia
Strokes can result from cerebral hemorrhage or cerebral ischemia
Disruption of blood supply to the brain area
Ischemic strokes often induce brain damage via excitotoxicity
Which neurotransmitter is most associated with excitotoxicity
Excessive release of excitatory amino acids
Glutamate is released when blood vessels are blocked
Excess glutamate release
Causes release of glutamate on receiving cells
Can kill postsynaptic cell
NMDA receptor blockers
What factors cause contusions
Injury includes bleeding without laceration caused by brain hitting the skull, which can be countrecoup
What is meant by contrecoup contusions
When the injury occurs on the opposite side of the head from where the initial impact occurred
Encephalitis
Inflammation in the brain resulting from infection
Neurotoxins can induce toxic psychosis
Which neurotoxins led to the term mad hatter and crackpit entering the English vernacular
Heavy metals like mercury and lead poisoning can result in brain damage
tonic portion seizures
Epilepsy can induce tonic-clonic seizures;
the tonic portion involves rigidity of the muscles,
clonic portion seizures
Epilepsy can induce tonic-clonic seizures;
The clonic portion results in jerking movements
Neuropathological changes associated with Alzheimer’s disease
Amyloid plaque
Neurofibrillary tangles
Neuronal loss
The loss of neurons is associated with the aberrant folding of tau proteins and amyloid beta proteins
What type of anatomical pathologies does this aberrant folding induce
Leads to the formation of neurofibrillary tangles from tau and amyloid plaques within the brain causing significant neuronal loss and disruption of neural networks ultimately leading to cognitive decline and dementia symptoms
Anterograde
2 types of neurodegeneration
Degeneration occurring away from the cell body typically following an injury to the axon
Retrograde
2 types of neurodegeneration
Degeneration happens toward the cell body, meaning the damage spread backward from the injury site to the neuron itself
How does transneuronal degeneration lead to the spread of neurodegeneration?
Causing damage to neurons that are directly connected to initially injured neurons through synapses
What is the role of collateral sprouting in the regeneration of the CNS
Enabling uninjuried neurons to extend new sprouts into areas that have lost their nerve supply due to injury
