MEDI2300 - Anatomy Test Flashcards
(104 cards)
1
Q
Identify the 8 cranial bones of the skull (including which bones are paired vs unpaired)?
A
2
Q
Which cranial suture lies between:
The frontal and parietal bones
The parietal and occipital bones
Between parietal bones
A
Coronal suture = between frontal & parietal
Lambdoid suture = between parietal & occipital
Sagittal suture = between both parietals
3
Q
What bones form the anterior, middle and posterior cranial fossa?
A
Anterior = Frontal, ethmoid, sphenoid bones
Middle = Sphenoid, temporal bones
Posterior = Occipital, temporal, parietal, sphenoid bones
4
Q
A
5
Q
A
6
Q
What passes through the following foramina?
Carotid canal:
Foramen spinosum:
Foramen magnum:
A
Carotid canal = Internal carotid artery, deep petrosal nerve and carotid plexus
Foramen spinosum = Middle meningeal artery, middle meningeal vein and meningeal branch of the mandibular nerve (CN V3)
Foramen magnum = Spinal cord, vertebral arteries, anterior and posterior spinal arteries
7
Q
Identify where cranial suture meet (aka fontanelles)?
A
- Bregma
- Lambda
- Pterion
- Nasion
8
Q
Identify features of the sphenoid bone?
A
- Lesser wing
- Greater wing
- Sellae turcica (‘Turkish saddle’)
- Pterygoid plates
9
Q
A
10
Q
What dinosaur is anatomically relevant to the sphenoid bone?
A
Pterodactyl:
“Pterygoid” in the sphenoid bone means “wing-like”, similar to the wings of the pterodactyl
11
Q
Identify features of the ethmoid bone?
A
- Cribriform plate
- Crista galli
12
Q
Which cranial nerve passes through the cribriform plate and is it moving into or out of the skull? Why?
A
Olfactory nerve (CN I):
CN I moves into the skull, because it is a sensory nerve where it’s olfactory nerve’s fibers carry olfactory information from the nasal cavity, through the cribriform plate to reach the olfactory bulb in the brain
13
Q
A
*Note: Cerebellum means ‘little brain’
14
Q
Identify the lobes, gyrus and sulcus of the brain?
A
15
Q
Identify this structure?
A
- Insula lobe
- Limbic lobe (a group of brain structures involved in emotion and memory)
16
Q
Identify this structure?
A
Longitudinal fissure
17
Q
A
- Precentral gyrus
- Central sulcus
- Postcentral gyrus
18
Q
What type of signalling (motor or sensory) is associated with the precentral and postcentral gyrus and what cortexes do they contain?
A
Precentral gyrus = motor signalling as it contains the primary motor cortex
Postcentral gyrus = sensory signalling as it contains the primary somatosensory cortex
19
Q
What are the primary functions of each lobe of the brain?
A
Frontal = Motor control (primary motor cortex), higher level cognitive functions (planning, decision making, problem solving), speech production (Broca’s area)
Parietal = Somatosensory processing (primary somatosensory cortex), spatial awareness, body orientation
Occipital = Vision (primary visual cortex)
Temporal = Auditory processing (primary auditory cortex), understanding speech (Wernicke’s area), memory (hippocampus lies deep here)
Insula = Pain and emotion integration, interoception (internal body awareness), taste perception
Limbic system = Emotion regulation, memory formation, motivation and reward (includes amygdala, hippocampus)
20
Q
Define the ‘homunculus man’?
A
A topographic map (visual map) showing how body parts are disproportionately represented in the brain’s motor and sensory cortices
- Body regions with fine movement or high sensitivity (like the hands and lips) appear larger and trunk, back, leg and foot smaller.
21
Q
What is the function of this structure?
A
Corpus callosum:
A bundle of nerve fibres that connects the left and right cerebral hemispheres, allowing them to communicate with each other
22
Q
What is the function of this structure?
A
Thalamus:
It is a central relay station for processing all sensory and motor signals (except smell) before being sent to the cerebral cortex for interpretation
23
Q
Identify this structure?
A
Hypothalamus
24
Q
Differentiate between grey matter and white matter in the brain?
A
Grey matter:
Is superficial, primarily consists of neuron cell bodies and dendrites, where information processing and integration occur.
White matter:
Is deep, primarily consists of myelinated axons, which facilitate communication between different areas of the brain and body.
25
Identify this structure?
Corona radiata ('crown of radiance')
26
Identify this structure and the bone that protects it?
Pituitary gland and is protected by the sella turcica of the sphenoid bone
27
How can the pituitary gland be surgically accessed?
Transnasal (or transsphenoidal): Involves accessing the pituitary gland via the sphenoid sinus in the nasal cavity, which is located behind the nose.
Trans-cranial approaches: Involves making an incision in the skull to access the pituitary from above.
28
Identify this structure and what it connects?
Cerebral peduncles:
Large bundles of nerve fibers in the midbrain that carry signals between the cerebrum to the brainstem and spinal cord
29
What is the significance of the name 'peduncles'?
Peduncles means 'little feet' of the cerebrum, since they are the two stalks that attach the cerebrum to the brainstem
30
Identify the three parts of the brainstem?
*Mid brain, pons, medulla oblongata
31
Identify this structure and the sense it is primarily associated with?
Superior colliculi (vision)
32
Identify this structure and the sense it is primarily associated with?
Inferior colliculi (hearing)
33
Identify this structure?
34
Identify these structures and what part of the brainstem they are located in?
The olives and pyramids are located in the medulla oblongata of the brainstem
35
Why are the pyramids important?
They are important for voluntary movement control because they are the location where most motor nerve fibre tracts from the brain decussate (cross over) to the opposite side of the body
36
What is 'closed' vs 'open' medulla referring to?
It's referring to the regions of the medulla:
Closed medulla region (lower part): The central canal (a narrow tube filled with CSF) is enclosed inside the medulla, just like in the spinal cord.
Open medulla region (upper part): The central canal opens up into a wider space called the fourth ventricle, which is visible on the back (dorsal side) of the brainstem.
37
1. Vertebral arteries
2. Basilar artery
3. Internal carotid arteries
4. Posterior cerebral arteries
5. Middle cerebral arteries
6. Anterior cerebral arteries
7. Posterior inferior cerebellar arteries
8. Anterior inferior cerebellar arteries
9. Superior cerebellar arteries
10. Posterior communicating arteries
11. Anterior communicating artery
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*Note: This cadaver does not label the posterior and anterior inferior cerebellar arteries
40
Which regions of the cortex do the 3 cerebral arteries supply blood to?
41
What artery is involved if a patient experienced motor and sensory deficits in their right leg following a stroke?
The anterior cerebral artery supplies the medial part of the frontal and parietal lobes, which contain the leg area of the motor and sensory homunculus. Since the deficit is on the right side, the left ACA is involved due to contralateral control
42
Which artery is most at risk if a patient experiences a severe headache following a sporting injury where they were accidentally hit in the temple with a baseball?
The middle meningeal artery runs deep to the pterion (deep to the temple). A blow to the temple can fracture this thin bone and rupture the artery, risking an epidural hematoma
* Note: The middle meningeal artery is a branch of the maxillary artery, which is a branch of the external carotid artery
43
Blocking the blood flow of the left middle cerebral artery will primarily affect which lobe of the brain?
The dura mater of the left frontal, temporal and parietal regions (supplies blood to the dura mater in these regions, and not the lobes themselves)
44
Lateral ventricle --> interventricular foramen --> third ventricle --> cerebral aqueduct --> forth ventricle --> central canal
*Note: This is a ventricular model, which involves solidifying empty spaces in the brain + the lateral ventricle has an anterior, inferior and posterior horn
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46
Which ventricles does the cerebral aqueduct connect?
The cerebral aqueduct is a narrow canal that allows CSF to flow between the third and fourth ventricles
47
What is located within the ventricles?
Ventricles (fluid-filled spaces) contain CSF, which is essential for cushioning and protecting the brain. The ventricles are lined by ependymal cells, which form the choroid plexus (responsible for producing CSF)
48
Identify the structure coloured red?
Choroid plexus (site of CSF production and is located on all the ventricles)
49
Identify the meninges of the brain?
50
Identify the meninges of the spinal cord?
51
Which meninges forms the dural folds?
Dura mater (it is the most superficial and 'durable' layer)
52
Identify the 4 dural folds of the brain?
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What is the importance of this structure?
Diaphragma sellae:
Is a horizontal fold of dura mater that forms the roof of the sellae turcica (the bony cavity that houses the pituitary gland). It separates the pituitary gland from the intradural space.
57
What is the name of the space found between the arachnoid and pia mater, and what is found in there?
Subarachnoid space (contains CSF)
58
Where are the sinuses in the brain found?
Within the 4 dural folds
59
Identify the sinuses of the brain?
1. Superior sagittal sinus
2. Inferior sagittal sinus
3. Straight sinus
4. Transverse sinus
5. Sigmoid sinus
60
Identify the sinuses of the brain?
61
How is CSF flow related to dural sinuses?
CSF is reabsorbed into the dural venous sinuses through arachnoid villi on arachnoid granulations within the subarachnoid space. Once inside the sinus, CSF mixes with venous blood and is returned to the systemic circulation via the internal jugular veins (to metabolise excess CSF).
62
Between which layers of meninges do you find CSF?
Subarachnoid space (between the arachnoid mater and pia mater; the two inner meninges)
63
CLARIFY WHICH SPINAL NERVES
Identify these structures and explain why these structures exist at these levels?
Cervical enlargment (C3/4-T1 spinal nerves)
Lumbosacral enlargment (L2-S3 spinal nerves)
They exist to accommodate the increased number of nerve cells and connections required for processing sensory and motor information related to the upper and lower limbs
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**Filum terminale (aka terminal thread)**: A fibrous band that connects the spinal cord to the coccyx
**Conus medullaris**: The lower end of the spinal cord that tapers off around the lumbar vertebrae
**Cauda equina (‘horses tail’)**: A collection of lumbosacral nerve roots that surround the conus medullaris
66
**Filum terminale (aka terminal thread)**: A fibrous band that connects the spinal cord to the coccyx
**Conus medullaris**: The lower end of the spinal cord that tapers off around the lumbar vertebrae
**Cauda equina (‘horses tail’)**: A collection of lumbosacral nerve roots that surround the conus medullaris
67
Which layer of meninges is this structure made from?
Denticulate ligaments:
Are triangular extensions formed from pia mater that attach the spinal cord to the dura mater to restrict rotation and movement within the spinal canal
68
What makes grey and white mater different in the spinal cord?
**Grey matter**: Is deep, consists primarily of neuron cell bodies, dendrites, and synapses for information processing.
**White matter**: Is superficial, and composed mainly of bundles of myelinated axons, which facilitate faster signal transmission between different areas of the spinal cord and the brain.
*Note: Grey mater is superficial & white mater deep in the brain, whereas, white mater is superficial and grey mater deep in the spinal cord*
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*Note: The lateral horn is also called the Intermediolateral horn
70
Which region do you find the intermediolateral horn?
Lateral region of T1 to L2 spinal cord segments
71
*Note: The fasciculus gracile and fasciculus cuneate both form the dorsal column (aka dorsal column-medial lemniscus)
72
What is the function of the corticospinal tract (aka pyramidal tract)?
It is the primary motor tract (neural pathway) that transmits voluntary motor commands from the cerebral cortex to the spinal cord for skilled, conscious control of limbs and trunk muscles
73
What is the function of the spinothalamic tract?
It is a crucial sensory tract that transmits sensory information about pain, temperature and crude touch from the body to the thalamus, allowing our body to react to potentially harmful stimuli
74
Explain the pathway of the corticospinal tract?
Upper motor neurons from the primary motor cortex (areas 4 and 6 of the frontal lobe) have axons that descend through the internal capsule, cerebral peduncles, pons, and gather in the medullary pyramids of the medulla. The axons decussate (cross over) at the pyramidal decussation (junction of the medulla and spinal cord), descend in the lateral corticospinal tract of the spinal cord. These UMNs terminate in the dorsolateral region of the spinal cord's grey matter, where they synapse with lower motor neurons. LMNs then project their axons out of the spinal cord to innervate distal skeletal muscles, especially flexor muscles, enabling precise voluntary movement.
75
Explain the pathway of the spinothalamic tract?
First-order (primary afferent) neurons have their cell bodies in the dorsal root ganglion to detect stimuli from skin mechanoreceptors and enter the spinal cord, where they immediately synapse in the dorsal horn.
Second-order (primary afferent) neurons originate in the dorsal horn, decussate (cross over) at the same spinal level, and ascend contralaterally in the spinothalamic tract along the anterolateral (ventral) surface of the spinal cord to the ventral posterior nucleus of the thalamus (but in a different area to the synapse of the medial lemniscal).
Third-order neurons (primary afferent) begin in the thalamus and project to various areas of the cerebral cortex, including the primary somatosensory cortex, allowing conscious perception of pain and temperature.
76
What is the acronym for naming cranial nerves?
Oh - Olfactory
Oh - Optic
Oh - Oculomotor
To - Trochlear
Touch - Trigeminal
And - Abducens
Feel - Facial
Very - Vestibulocochlear
Good - Glossopharyngeal
Velvet - Vagus
And - Accessory
Heaven - Hypoglossal
77
What is the acronym for knowing the 'modality of cranial nerves (aka sensory, motor or both)?
Some
Say
marry
Money
But
My
Brother
Says
Big
Brains
Matter
More
78
What are the functions of CN I to CN VI?
CN I - smell
CN II - vision
CN III - eye movement, eyelid elevation, pupil constriction
CN IV - eye movement
CN V - facial sensation (V1-V3), muscles of mastication
CN VI - eye movement
79
What are the functions of CN VII to CN XII?
CN VII - muscles of facial expression, taste (anterior 2/3 of tongue), lacrimation, salivation
CN VIII - hearing, balance
CN IX - taste (poster 1/3), salivation (parotid), swallowing
CN X - parasympathetic control of heart, lungs, GI tract, voice, swallowing
CN XI - head and shoulder movement
CN XII - tongue movement
80
What nerves are specified in the lab sheet to know?
Olfactory
Optic
Oculomotor
Trigeminal
Facial
Abducens
Hypoglossal
81
1. Olfactory nerve
2. Optic nerve
3. Oculomotor nerve
4. Trochlear nerve
5. Trigeminal nerve
6. Abducens nerve
7. Facial nerve
8. Vestibulocochlear nerve
9. Glossopharyngeal nerve
10. Vagus nerve
11. Accessory nerve
12. Hypoglossal nerve
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83
84
1. Vestibulocochlear nerve
2. Trigeminal nerve
3. Glossopharyngeal nerve
4. Oculomotor nerve
5. Hypoglossal nerve
6. Vagus nerve
7. Olfactory tract (aka olfactory nerve)
8. Facial nerve
9. Accessory nerve
10. Abducens nerve
11. Optic chiasm (aka optic nerve)
12. Trochlear nerve
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86
1. Superior cerebellar peduncle
2. INFERIOR cerebellar peduncle
3. MIDDLE cerebellar peduncle
*Note: Cerebellar peduncles connect the cerebellum to the midbrain and brainstem (SCP to midbrain, MCP to pons and ICP to medulla)
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88
Identify and explain?
Cerebellar peduncles: A type of relay nuclei that serve as the primary connection between the cerebellum and brainstem
89
Identify the following structures in the anterior cerebellum?
90
What information (afferent/efferent) is transmitted via each peduncle?
SCP = efferent information from the deep cerebellar nuclei to the motor nuclei of the thalamus and the red nucleus
MCP = afferent information from the cerebral cortex via the pontine nucleus to the cerebellum
ICP = afferent information from the spinal cord, brainstem, and vestibular nuclei to the cerebellum
91
Would a lesion of the cerebellum result in ipsilateral or contralateral effects?
Ipsilateral effects because proprioceptive input from the spinocerebellar pathway and cerebellar output to lower motor neurons both influence the same side of the body, despite the cerebellar efferents decussating before reaching the cortex.
92
What system (including structures) is responsible for emotion and memory?
Limbic system = Amygdala, hippocampus, fornix, mammillary bodies, anterior thalamic nuclei, cingulate gyrus
93
Identify the structures of the limbic system?
1. Cingulate gyrus
2. Fornix
3. Thalamus (contains the anterior thalamic nuclei)
4. Mamillary body
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96
97
How does the amygdala-hippocampus relationship impact the creation of memories?
Because the amygdala is immediately anterior to the hippocampus, the amygdala adds emotions to the memories formed by the hippocampus, making emotionally charged memories more likely to be remembered
98
Identify the components of the basal ganglia?
99
Identify the components of the basal ganglia?
1. Caudate nucleus
2. Thalamus
3. Putamen
4. Subthalamic nucleus
5. Substantia nigra
*Note: The globus pallidus internus and externus are not visible in this cadaver
100
1. Globus pallidus internus
2. Globus pallidus externus
101
Basal ganglia:
1. Caudate nucleus
2. Thalamus
3. Putamen
4. Subthalamic nucleus
5. Substantia nigra
Non-basal ganglia:
6. Amygdala (or hippocampus)
7. Red nucleus
8. External capsule
9. Internal capsule
10. Fornix
11. Lateral ventricle
12. Corpus callosum
13. Cingulate gyrus
102
What is the major function of the direct vs indirect pathway of the basal ganglia?
Direct pathway = Facilitates movement by promoting motor activity
Indirect pathway = Inhibits movement by suppressing unwanted motor activity
103
Describe the interactions between nuclei that contribute to their function in the DIRECT pathway of the basal ganglia?
1. Excitatory input from the motor cortex to the striatal cells (caudate nucleus and putamen) increases inhibition of the globus pallidus internus (GPi) and substantia nigra
2. This reduces inhibition of the thalamus, making it more active to excite the motor cortex to promote movement
Motor cortex → striatal cells → GPi & SN → thalamus → motor cortex → increases movement
104
Describe the interactions between nuclei that contribute to their function in the INDIRECT pathway of the basal ganglia?
1. Excitatory input from the motor cortex to the striatal cells (caudate nucleus and putamen) increases inhibition of the globus pallidus externus (GPe)
2. This reduces inhibition of the subthalamic nuclues (STN), making it more active to excite the globus pallidus interna (GPi)
3. GPi then strongly inhibits the thalamus, making the thalamus less able to stimulate the motor cortex, leading to suppression of movement.
Motor cortex → striatal cells → GPe → STN → GPi → thalamus → motor cortex → suppresses movement
