Neuroanatomy 2 (7) Flashcards
(96 cards)
1
Q
where is the cerebellum located?
A
posterior cranial fossa
2
Q
the cerebellum sits inferior to what? and posterior to what?
A
occipital and temporal lobes
pons and 4th ventricle
3
Q
what cerebellum is separated to the cerebrum by what?
A
tentorium cerebelli
4
Q
what are the major functions of the cerebellum?
A
coordinates and regulates movement, posture, and balance control
5
Q
the cerebellum functions in ?
A
proprioception
6
Q
what is proprioception
A
the perception or awareness of the position and movement of the body
7
Q
the cerebellum has 2 hemispheres joined by the ?
A
vermis
8
Q
each hemisphere is sub-divided into 3:
A
- anterior
- posterior
- flocculonodular
9
Q
the lobes of the hemispheres are separated by ?
A
two transverse fissures
10
Q
what are the two transverse fissures and what do they separate?
A
primary fissure - anterior - posterior lobe
posterolateral fissure - posterior - flocculonodular
11
Q
what does anterior and posterior lobes do
A
provide subconscious movements
12
Q
what does the flocculonodular lobe?
A
regulates equilibrium
13
Q
what is the “worm-like” part that separates the 2 hemispheres?
A
vermis
14
Q
what are the gyri-like convolutions on the surface of the cerebellum
A
foli
15
Q
What is the cerebellar cortex made of?
A
A single, sheet-like structure less than 1 mm thick, folded like an accordion and fused at the midline.
16
Q
What is each fold of the cerebellar cortex composed of?
A
An inner white matter core surrounded by gray matter.
17
Q
What is the white matter of the cerebellum called?
A
Arbor vitae.
18
Q
Where is the gray matter of the cerebellum located?
A
Peripherally arranged around the arbor vitae.
19
Q
What are the three pairs of deep cerebellar nuclei?
A
Fastigial, interposed (emboliform + globose), and dentate.
20
Q
Which deep cerebellar nuclei are associated with voluntary movement?
A
Dentate and interposed nuclei.
21
Q
Which deep cerebellar nucleus is associated with balance?
A
Fastigial nucleus.
22
Q
What are cerebellar peduncles?
A
Large white matter pathways that connect the cerebellum with other CNS structures.
23
Q
What are the three cerebellar peduncles?
A
Superior, middle, and inferior peduncles.
24
Q
Which cerebellar peduncle is primarily efferent (outgoing from the cerebellum)?
A
The superior cerebellar peduncle.
25
Which cerebellar peduncles are primarily afferent (incoming to the cerebellum)?
The middle and inferior cerebellar peduncles.
26
what are the 3 cerebellar pathways?
vestibulocerebellum, spinocerebellum, and cerebrocerebellum
27
what are the functions of vestibulocerebellum?
- balance
- coordination of eye movements
28
What is the major input to the vestibulocerebellum?
Vestibular fibers from the vestibulocochlear nerve (CN VIII) and vestibular nuclei.
29
What is the major output pathway from the vestibulocerebellum?
Through the fastigial nucleus.
30
What are the major output tracts of the vestibulocerebellum?
Vestibulospinal tract (motor balance)
Reticulospinal tracts (motor influences)
Medial longitudinal fasciculus (eye movement coordination)
31
What is the function of the medial longitudinal fasciculus in the vestibulocerebellum?
Interconnects the oculomotor, trochlear, and abducens nuclei in the brainstem to coordinate eye movements.
32
What common clinical sign is associated with a lesion in the vestibulocerebellum?
Nystagmus.
33
What is nystagmus?
Rapid, involuntary eye movements.
34
What are the three types of nystagmus based on direction?
Horizontal (side to side)
Vertical (up and down)
Rotary (circular)
35
What is the primary function of the spinocerebellum?
Adjusts movements as they occur by providing corrective feedback to fine-tune motor skills.
36
What are the major inputs to the spinocerebellum?
Proprioceptive input from the periphery
A copy of motor commands from the primary motor cortex
37
Through which cerebellar nuclei does the spinocerebellum send its output?
Interposed nuclei (globose and emboliform).
38
What are the major output tracts of the spinocerebellum?
Rubrospinal and corticospinal tracts.
39
What are the main functions of the cerebrocerebellum?
Planning movements
Rapid alternating movements
Fine motor dexterity
Initiation, termination, coordination, and timing of movements
Motor learning
40
What are the major input pathways to the cerebrocerebellum?
Corticopontocerebellar pathway (from premotor and association cortex)
Olivocerebellar pathway
41
Through which cerebellar nucleus does the cerebrocerebellum send its output?
Dentate nucleus.
42
What are the major output tracts of the cerebrocerebellum?
Corticospinal and rubrospinal tracts.
43
What is ataxia?
An inability to coordinate muscle activity during voluntary movement; most often due to disorders of the cerebellum or the posterior columns of the spinal cord; may involve the limbs, head, or trunk
44
What is dysarthria, and what causes it in cerebellar lesions?
Ataxia of laryngeal muscles causing jerky speech, separated syllables, and varying sound intensities.
45
What is cerebellar nystagmus?
Tremor of the eyeballs occurring when trying to fix gaze on a peripheral object, due to ocular muscle ataxia.
46
What is truncal ataxia, and how does it affect gait?
Inability to maintain upright posture, resulting in an unstable, wide-based gait with irregular steps and lateral swaying
47
What is dysmetria?
Inability to judge distance, resulting in overshooting or overcompensating movements; leads to intention tremors
48
What test is commonly used to detect dysmetria?
Finger-to-nose and heel-to-shin tests.
49
What is dysdiadochokinesia?
Loss of the ability to perform rapid alternating movements; tested by rapidly flipping the hand palm up and down.
50
What is hypotonia, and how is it related to cerebellar lesions?
Reduced muscle tone due to cerebellar dysfunction.
51
What is asynergia?
Lack of coordination among muscle groups during complex movement, leading to decomposition of movement into isolated steps.
52
What are the main survival-related behaviors controlled by the limbic system?
Feeding, reproduction, caring for young, and fight-or-flight responses.
53
What functions are associated with the limbic system?
Emotion, behavior, survival instincts, memory (spatial, short-term, long-term), learning, motivation, and social processing.
54
Where is the limbic system located?
Inferior to the cerebral cortex, lateral to the thalamus, and superior to the brainstem.
55
Where is the amygdaloid body located?
Adjacent to the hippocampus, one in each hemisphere.
56
What are the main functions of the amygdala?
Emotion regulation (pleasure, fear, anxiety, anger), behavioral learning, and emotional memory formation.
57
What sensory input does the amygdala receive from the olfactory bulbs?
Odor cues associated with positive or negative emotional responses.
58
What are the key roles of the hippocampus?
Learning new information, spatial memory, short/long-term memory, and associative memory.
59
What memory functions is the hippocampus primarily involved in?
Formation of new memories, not retrieval of distant ones.
60
What is the main memory and learning pathway involving the hippocampus?
Hippocampus → Fornix → Mammillary Bodies → Anterior Thalamic Nucleus → Limbic Cortex → Hippocampus.
61
What role does the hippocampus play in navigation?
Spatial orientation and remembering places/routes.
62
What is the fornix, and what does it do?
Output fibers of the hippocampus that allow it to communicate with other cortical areas; involved in memory recall.
63
What are the mammillary bodies involved in?
Formation of episodic memory, olfactory relay, and connections with hippocampus, amygdala, and thalamus.
64
Damage to the mammillary bodies is associated with what condition?
Thiamine deficiency (e.g. Wernicke-Korsakoff syndrome).
65
What does the limbic cortex do?
Controls behavior, learning, and short-term memory storage; connects emotional input to memory via hippocampus.
66
How does short-term memory become long-term memory?
Through consolidation via rehearsal and meaningful association; involves biochemical neuron changes.
67
How does the amygdala influence memory consolidation?
Emotional input enhances memory strength; the more emotional, the stronger the amygdalar activity and the memory.
68
What is an example of the amygdala modulating memory?
A smell or song triggering a vivid memory due to emotional association.
69
What common 1950s treatment for epilepsy caused memory issues?
Removal of the hippocampus.
70
What was the main consequence of hippocampal removal in epilepsy patients?
Inability to form new memories (anterograde amnesia).
71
What behavioral changes can result from amygdala destruction?
Docility, hypersexuality, impaired fear conditioning, and emotional learning deficits.
72
What happens to a person’s emotional response in fight-or-flight situations with amygdala damage?
The person may be unable to respond appropriately.
73
What is an example of impaired emotional learning from amygdala damage?
A child may not feel happiness or comfort when seeing their mother’s face.
74
What is hyperphagia and what causes it in the context of limbic damage?
Uncontrolled appetite; can result from amygdala damage.
75
What causes Korsakoff’s syndrome?
Chronic vitamin B1 (thiamine) deficiency, often due to alcoholism.
76
How does alcohol contribute to thiamine deficiency?
Alcohol decreases food intake, increases vitamin B requirements, and reduces absorption.
77
What brain structures are first affected in Korsakoff’s syndrome?
The anterior thalamic nucleus and mammillary bodies.
78
What are the key symptoms of Korsakoff’s syndrome?
Anterograde amnesia (can’t form new memories)
Confabulation (filling in memory gaps with imagined stories)
79
What is confabulation?
A plausible but imagined memory used to fill in memory gaps, commonly seen in Korsakoff’s syndrome.
80
What are the main bodily functions regulated by the hypothalamus?
Hormone regulation, temperature control, appetite, sleep, thirst, and emotions.
81
How does the hypothalamus influence other endocrine glands?
By releasing hormones that act on the pituitary, which then stimulates peripheral glands (like thyroid and adrenal).
82
What role does the hypothalamus play in the autonomic nervous system?
It regulates involuntary functions like heart rate, blood pressure, and digestion.
83
How does the hypothalamus regulate body temperature?
By responding to environmental temperature changes to maintain homeostasis.
84
How does the hypothalamus influence hunger and satiety?
It receives signals about energy needs and controls appetite and satiety behaviors.
85
What role does the hypothalamus play in sleep?
It helps regulate the sleep-wake cycle, affecting timing and quality of sleep.
86
How does the hypothalamus control hormone secretion in the body?
By producing releasing/inhibiting hormones that act on the pituitary gland.
87
What is the negative feedback loop in the hypothalamic-pituitary axis?
Hormone release from peripheral glands inhibits hypothalamic and pituitary hormone production.
88
What is the hypophyseal portal system?
A blood vessel system that carries hypothalamic hormones directly to the anterior pituitary.
89
Where are oxytocin and ADH produced and released?
Synthesized in hypothalamic neurons, stored/released by the posterior pituitary.
90
What stimulates oxytocin release?
Uterine stretching and nipple stimulation.
91
What are the functions of oxytocin?
Uterine contraction, milk ejection, emotional bonding.
92
What stimulates ADH (vasopressin) release?
Decreased blood pressure, dehydration, and increased blood osmolarity.
93
What are the effects of ADH?
Reduces urine output, decreases sweating, causes vasoconstriction.
94
What symptoms occur with hypothalamic damage?
Disruption in hormone balance, appetite, sleep-wake cycle, and temperature regulation.
95
What is diabetes insipidus and how is it related to the hypothalamus?
A condition caused by a lack of ADH, leading to excessive thirst and urination.
96
What causes diabetes insipidus?
Head injury, infections, tumors, or surgery affecting the hypothalamus/posterior pituitary.
