Locomotion 4 Flashcards
(90 cards)
1
Q
What is the CNS and PNS made up of
A
CNS = Central Nervous System = BRAIN & SPINAL CORD PNS = Peripheral Nervous System = NERVES & GANGLIA
2
Q
What are nuclei and ganglia
A
1) Nuclei -> collection of neuronal cell bodies within the CNS
§ On the surface of the cerebrum and cerebellum (cerebral and cerebellar cortex), spinal cord (grey matter)
2) Ganglia -> collections of neuronal cell bodies outside the CNS
§ Peripheral ganglia
3
Q
What are the 3 types of neurons and the percentage of total neurons
A
1) Sensory neuron - 15% are sensory
2) Interneuron - 80%
3) Motor neuron - 3% are effector neurons -> process attached to the glands or muscles to contract or secrete
4
Q
What is grey and white matter
A
Grey matter
- Consists of neuron cell bodies and supporting cells (glia)
- Appears pinkish grey in fresh CNS material
- unmyelinated but still insulated my myelin
White matter
- Consists of networks of neuron cell processes and their supporting cells
- appears white because of the high content of myelin
- Majority of the nervous system
5
Q
Spinal nerves what are they formed from at what level of the vertebrae and how named in cervical then thoracic region
A
- Each spinal nerve have dorsal and ventral branches, spinal nerves formed when dorsal and ventral roots joint at intervertebral foramen
Cervical
C1 = skull and C1 (cranial to C1)
HOWEVER C8 between C7 and T1 therefore C8 cranial to T1 and T1 is caudal to T1 (between T1 and T2)
From then on all spinal nerves are caudal to corresponding vertebrae
6
Q
Where is the information coming from or going in the dorsal, ventral and intermediate horn of the spinal cord
A
Dorsal horn
- information coming within -> SENSORY NEURONS
- general somatic and visceral afferent (sensory) -> muscle and glands
Ventral horn
- information going out of the spin - MOTOR NEURONS
- general somatic efferent - voluntary muscle movement
Intermediate horn
- INTERNEURONS generally general visceral efferent (glands and organ control)
- not present in cervical spinal
7
Q
How many spinal nerves are within the dog in each region: Cervical, thoracic, lumbar, sacral and caudal and overall
A
cervical - 8 pairs thoracic - 13 pairs lumbar - 7 pairs sacral - 3 pairs caudal - variable Overall general 36 pairs
8
Q
location of the cerebral hemispheres, cerebellum and brain stem within the brain
A
Cerebral hemisphers - dorsally and rostrally
Cerebellum - dorsally and caudally
Brain stem - central, ventral and caudal part of the brain
9
Q
Somatic and autonomic nervous systems what convey impulses to
A
Somatic - skeletal muscle - voluntary movement
Autonomic - smooth muscle of viscera, blood vessels, cardiac muscles and glands
10
Q
where are the origins within the spinal cord for parasympathetic and sympathetic nerves
A
Parasympathetic nerves have a cranial or sacral origin
Sympathetic nerves have a thoracic or lumbar origin and accompany the blood vessel to all parts of the body
11
Q
What are the meninges and why does it consist of
A
- The connective tissue membranes which cover the brain and spinal
Consists of - dura mater, arachnoid mater and pia mater (external to internal)
- epidural space: external to the dura mater and contains fat and the vertebral venous plexi
○ Obliterated in the med cervical region CS (C2, C4) by fusion of the dura with the periosteum
12
Q
Dura Matter other name, what is it and function
A
Pachymeninx)
- Dense, tough fibrous covering
- Encloses the spinal roots as they leave the spinal cord and fuses with the epineurium at the intervertebral foramen
13
Q
Arachnoid Matter what is the other name, structure, where run and structures wtihin
A
Leptomeninges)
- Thin/delicate
- Just medial to the dura mater
1) subarachnoid space lies between the arachnoid and pia mater and contains cerebrospinal fluid (CSF)
2) arachnoid trabeculae are fine meningeal filaments that cross the arachnoid space between the arachnoid mater and the pia mater
14
Q
What is the function of the cerebrospinal fluid
A
○ Cerebrospinal fluid maintained at positive pressure compared to blood pressure -> functions as a fluid cushion that helps the central nervous system
15
Q
Pia Mater what is the other name, structure, function and ligament within
A
- Very delicate membrane which is fused to and closely follows the contours of the CNS, makes up the blood brain barrier
- Denticulate ligaments form on the lateral aspect of the spinal cord between the arachnoid and pia mater half way between succeeding spinal nerves
Ligaments help to suspend and stabilise the spinal cord in the vertebral canal
16
Q
What is the main artery that runs through the veterbral canal and what does it supply
A
Ventral longitudinal artery -> the main artery
○ Good blood supply including intercostal arteries
○ In the neck the vertebral artery supplies the spinal cord through branches into intervertebral spaces of each vertebrae as runs up towards the head
17
Q
What cervical vertebrae articulates with part of a rub and where
A
- 7th cervical vertebrae has caudal costal fovea which articulate with the cranial part of the heads of the first pair of ribs
18
Q
Intervertebral disc where located and function
A
- Located between every vertebra expect between
○ Skull and C1
○ C1 and C2
○ The sacral vertebrae
Function: to unite the vertebrae and allow some movement between them - Thickest in the cervical and lumbar regions (especially lumbosacral joint)
19
Q
What are the 2 areas of the intervertbral disc and structure, which way do discs general prolapse and why
A
1) Annulus fibrosus
- which is a thick fibrous outer ring with fibres running obliquely between vertebrae
- Thicker ventrally so more discs prolapse dorsally than ventrally in degenerative joint disease
2) Nucleus pulposus
- An amorphous gelatinous centre to the disc (thus allowing some “give” in all directions
- Remnant of the notochord
20
Q
The presence of what in the thoracic region leads to disc rupture in thoracic region being rare
A
The presence of the intercapital ligament
21
Q
List the 6 ligaments of the spinal column
A
1) interspinous
2) yellow (ligamentum flava)
3) nuchal
4) supraspinous
5) ventral longitudinal
6) dorsal longitudinal
22
Q
Interspinous ligament where present and function
A
- Connect adjacent vertebral spines
- May blend dorsally with the supraspinous ligaments and laterally with the interspinalis muscles
23
Q
Yellow ligament what also called, where located and function
A
(Ligamentum flava)
- Loose thin elastic sheets between the arches of adjacent vertebrae
- Laterally they blend with the articular capsules surrounding the articular processes
Epidural space is medial to the yellow ligaments
24
Q
Nuchal ligament structure and where present
A
- Longitudinal yellow, elastic fibres with attach cranially to the caudal part of the spinous process of C2 and attaches caudally to the dorsal tip of the dorsal spinal process of T1
25
Supraspinous ligament where present and function
- Heavy bands that extends from T1 to C3 attaching to the dorsal spinous processes
- More important for preventing separation of the spinous processes during flexion of the vertebral column than are the Interspinous ligaments
26
Ventral and dorsal longitudinal ligaments where present
Ventral longitudinal ligament
- Lies on the ventral aspect of the vertebral bodies from the axis to the sacrum and is best developed in the caudal thorax
Dorsal longitudinal ligaments
- Lies along the dorsal aspect of the vertebral bodies (floor of the spinal canal)
- Extends from the dens of the atlas to the end of the vertebral canal in the caudal vertebrae
27
Atlantoaxial articulation how does this occur and held in place
- a pivot joint between the atlas and the axis that allows the head to rotate around the longitudinal axis
- the dens is a peg of bone running from cranial C2 onto the floor of the spinal canal of C1
○ held in place by the apical ligament of the dens (x3) and the transverse atlantal ligament
28
What are the synovial joints within the vertebrae for the cervical and thoracic
- 4 synovial joints within the vertebrae -> 2 cranial (cranial articular surfaces) and 2 caudal (caudal articular surfaces)
- More with the thoracic - ribs - 6 MORE as 3 on each side therefore has 10 SYNOVIAL JOINTS
○ Ribs articulation within the head between
i. cranial vertebrae and caudal costal fovea
ii. caudal vertebrae to the cranial costal fovea
○ Ribs articular within the tubercle between
i. caudal vertebrae to the transverse process
29
What is the white matter within the spinal cord divided into and what are they associated with
3 paired funiculi
1. Dorsal funiculus associated with ascending proprioceptive function - SENSORY FUNCTION
2. Lateral funiculus facilitates flexor function - MOTOR FUNCTION
3. Ventral funiculus facilitates extensor function - MOTOR FUNCTION
30
What are the 3 structures at the end of the spinal cord and the extent of the spinal cord in dogs, cat, and horses
1. conus medullaris is the tapered caudal end of the spinal cord.
2. cauda equina is the nerve roots coming off the conus medullaris or the nerve roots and the conus medullaris
3. filum terminale is the very terminal portion of the spinal cord tissue which is formed by ependymal and glial cells
○ Dog L6 or L7
○ Cats L7
○ Horse S2
31
List the 6 anatomical division of the spinal cord, describe and how best seen
1) dorsal median septum is found in the dorsal midline
2) ventral median fissure is the cleft in the ventral midline
3) dorsolateral sulcus - where the dorsal roots enter the cord
4) ventrolateral sulcus (usually indistinct) - where the ventral roots enter the cord
5) small central canal lined with ependyma and filled with CSF - a remnant of the neural canal
6) sulcus limitans a longitudinal groove on the lateral wall of the spinal cord which divides the alar and basal plates.
Visualisation of these structures is best seen under low power magnification
32
What are the Lower motor neurons and upper motor neurons and their function
1) Lower motor neurons (LMN)
- Efferent neurons connecting the CNS with the target organ
- Go straight to the motor end plate
2) Upper motor neurons (UMN)
- Efferent neurons within the CNS that influence (mostly inhibit) activity of the LMN
- Contained entirely within the CNS however if in spinal cords within the lateral and ventral horns
33
What results from with dysfunction of LMN and UMN
LMN - hyporeflexia, atonia, neurogenic atrophy (acute and severe)
UMN - hyperreflexia and hypertonia due to loss of descending inhibitory influence on LMNs
34
What tracts are found in the peripheral and central location within the spinal cord
PERIPHERAL LOCATION = ascending and long tract
- More likely to be damaged as longer and superficial
CENTRAL LOCATION - descending and short tracts
35
What tracts are found within the dorsal, lateral and ventral funiculi (ascending or descending and what muscles act on)
Dorsal funiculi - primarily contains ascending proprioceptive tracts
1. Hindlimb tracts -> dorsal and central
2. Forelimb tracts -> deeper and more lateral
Lateral funiculi - ascending and descending tracts
- Descending tracts generally facilitate flexors
Ventral funiculi - descending tracts
- Descending tracts generally facilitate extensors
36
What does one spinal nerve divide into and what does this supply
1) Dorsal branch - supplies the epaxial muscle and skin
2) Ventral branch - supplying the hypaxial muscle and skin
3) Ramus communicans - only in thoracic and cranial lumbar regions
37
Brachial plexus what are the main spinal nerves supplying this and what is the general rule for muscles corresponding spinal nerve
○ (C5), C6, C7, C8, T1, (T2)
- The more proximal muscle is on a limb, the more cranial is the spinal cord segment innervates it
○ EG - innervation shoulder arises C6,C7 and distal muscles arises T1/T2
38
Suprascapular and subscapular nerve what spinal nerves and muscles innovate
C6,C7
LATERAL MUSCLES OF THE SHOULDER AND SCAPULAR
- supraspinatus, infraspinatus
Subscapular - subscapularis
39
Musculocutaneous nerve what spinal nerves does it originate from and muscles it innovates
C6,C7,C8
| Cranial muscles of the arm, flexors of elbow, extensors of shoulder, biceps brachii, coracobrachialis, brachialis
40
Axillary nerve what spinal nerve does it originate from and muscles it innovates
C7,C8
| Caudal muscles of scapula and shoulder, shoulder flexors – deltoideus, teres major and minor, (subscapularis)
41
Radial nerve what spinal nerve does it originate from and muscles it innovates
C7,C8,T1,(T2)
| Caudal muscles of arm, extensors of elbow –triceps brachii, cranial muscles of forearm, carpal and digital extensors
42
Median and ulnar what spinal nerves does it originate from and muscles it innovates
C8,T1,(T2)
| Caudal muscles of forearm – carpal and digital flexors
43
Lateral thoracic and caudal pectoral nerve what spinal nerve does it originate from and muscles it innovates
Lateral thoracic - C8,T1 Deep pectoral and cutaneous trunci
| Caudal pectoral - C8,T1,(T2) Deep pectoral
44
Thoracodorsal what spinal nerve does it originate from and muscle it innovates
Thoracodorsal
| C8 Latissimus dorsi
45
Obturator nerve what spinal nerves does it originate from and muscles it innovates
L4-L6
| Adductor muscles - external obturator, pectineus, gracilis, adductor
46
Femoral nerve what spinal nerves does it originate from and muscles it innovates
L4-L6
| Hip flexors, stifle extenders, sartoriius, quadriceps
47
Caudal and cranial gluteal what spinal nerves does it originate from and muscles it innovates
L6-S2
Caudal - Hip extensors, superficial gluteal
Cranial - hip extensors and abductors, middle and deep gluteal, tesnor fasciae latae
48
Sciatic nerve what spinal nerves does it originate from and muscles it innovates
L6-S2
| - pelvic limb rotator - gemelli, quadratus femoris, internal obturator
49
Sciatic (muscular branch) what spinal nerves does it originate from and muscles it innovates
L6 - S2
| semimembranosus, semitendinosus, biceps femoris
50
Sciatic (common peroneal branch) what spinal nerves does it originate from and muscles it innovates
L6 - L7
cranial leg muscles - flexors of tarsus, extensors of digits - cranial tibila, long and lateral digital extensory, extensor longus, peroneuu longus and brevis
51
Tibial nerve what spinal nerves does it originate from and muscles it innovates
L7, S1
caudal leg muscles
- extensors of the tarsus and extensors of the digits - gastronemius, superficial digital flexor, popliteus, deep digital flexor
52
What is a dermatomses, cutaneous and autonomous zone
Dermatomes
- An area of skin innervated by one spinal nerve
Cutaneous zone is an area of skin innervated by one peripheral nerve (this often means that several spinal nerves are involved)
Autonomous zone is innervated by only one peripheral nerve
53
List the 6 steps in skeletal muscle contraction
Excitation contraction coupling
1. Motor neuron input from motoneuron
2. Muscle impulses cause SR to release calcium ions into cytosol
3. Calcium binds to troponin to change its shape
4. The position of tropomyosin is altered
5. Binding sites on actin are now exposed
6. Actin and myosin molecules bind via myosin cross‐bridges
54
Describe motor unit recruitment and the different types of motor units
• Smallest units have lowest threshold thus are activated first
○ Always recruited sequentially
○ Slow oxidative fibres -> motor unit 1 -> smaller in diameter so strength of contraction is lower
• Increased synaptic drive increases AP firing rate and activates additional motor units
○ Motor unit 2 -> Fast-oxidative fibres
○ Motor unit 3 -> Fast-glycolytic fibres
-Both fatigue faster therefore recruitment after slow fibres
Recruitment results in more myosin and actin cross-bridges
55
What are the 2 structures that control muscle activity locally where present what detect and 2 ways information is used
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- Golgi Tendon Organs
• Present in tendons
• Report muscle tension development
- Muscle Spindles
• Embedded within muscle
• Report muscle position, “Stretch”
This information is used in 2 ways
1. Appraisal of motor areas of the brain about muscle length and tension.
2. Control of muscle length and tension in a negative‐feedback fashion by means of local spinal reflexes
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56
Muscle spindle where located what fibres involves, what detects and then what occurs
located within fleshy part of muscle
• Intrafusal fibers parallel to extrafusal fibers
- Contraction of intrafusal fibres in same phase with extrafusal fibres (same level of contraction) -> doesn't contribute to the overall muscle contraction
Detects:
- rate of change at which the muscle fibers are stretched
- changes in length of muscle fibers
• aids in coordination and efficiency of muscle contraction
57
What are the 2 types of intrafusal fibres what detect and what is the nerve supply to intra and extra-fusial fibres
1) Nuclear bag fibres
- Large number nuclei packed into mid‐portion
- Sense onset of stretch
2) Nuclear chain fibres
- Nuclei in longitudinal row
- Sense sustained stretch
Nerve supply
• Efferent neuron which innervates intrafusal
fibres = gamma (ƴ) motor neuron
• Extrafusal fibres = alpha (α) motor neuron
Co-activated via different nerves
58
What are the 4 steps in the muscle spindle stretch pathway
1) Afferent input from sensory ending of muscle spindle fibre
2) Alpha motor neuron output to regular skeletal muscle fibres - extrafusal fibres
- Stretch reflex pathway (below) synapse directly with motor neuron
3) Gamma motor neuron output to contractile end portions of spindle fibre - intrafusal fibres
4) Descending pathways coming down co-activate and adjust through gamma motor neurons
3) and 4) in quick succession
59
Stretch reflex what are the 4 steps
Mono-synaptic
- Sensory neuron synapses DIRECTLY to the alpha motor neuron
1) Muscle spindle detects stretch of the muscle
2) Efferent - Sensory neurons conduct action potentials to the spinal cord
3) Sensory neuron synapse directly with alpha motor neuron
- Also synapse to the brain so it knows what is occurring - can adjust the response
4) Afferent - Alpha motor neuron conduct AP to the muscle causing it to contract
- resist being stretched
- Innervates the same muscle
60
Reciprocal innervation of the stretch flex what occurs
1st pathway - monosynaptic (above)
2nd pathway - polysynaptic
The antagonist muscle
An inhibiting interneuron existing between the sensory neuron and the alpha motor neuron that when stimulated prevents the further conduction of an AP to the antagonist muscle thus causing it to relax
3rd pathway - Signal to the brain -> can adjust the response
61
What are the steps in the tendon reflex
1) Collagen fibres contract and pull closer together which increases firing in the sensory receptor (tendon)
2) Efferent - The sensory neuron synapses with two interneurons at the spinal cord and an interneuron to the brain
1. Inhibitory interneuron that blocks the signal going back to the muscle attached to the tendon that increased in tension to relieve the tension
2. Afferent - Excitatory interneuron that induces a signal to a motor neuron that induces contraction of the antagonistic muscle
Another neuron to the brain -> able to adjust the response
62
Flexor (withdrawal) reflex what is the sensor and the 3 steps
SENSOR -> pain sensor
1) Synapses with interneuron of the spinal cord -> AP down motor of muscle to lift away from stimulus
2) Signal to the brain -> adjusts the response
3) Interneurons ascending and descending within the spinal cord
- Other interneurons are activated at the level of the spinal cord
○ Activate more motor-neurons -> activate more motor units -> stronger contraction of the muscle
63
Crossed extensor reflex what occurs with
1) Synapses with interneuron of the spinal cord -> AP down motor of muscle to lift away from stimulus
2) Signal to the brain -> adjusts the response
3) Interneurons ascending and descending within the spinal cord
- Other interneurons are activated at the level of the spinal cord
○ Activate more motor-neurons -> activate more motor units -> stronger contraction of the muscle
Additional
1) Other interneuron activated
2) Goes to motor neurons on the other side of the body
3) Induce development of tension in the opposing (antagonist) muscle on the other side of the body
- Hamstring on left contracting -> quadriceps now activated on the right to take the weight
64
What is involves with the mantenance of posutre and balance
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Reflexes
- Stretch
- Crossed‐extensor
• Afferent pathways involved in postural reflexes
- The eyes
- Vestibular apparatus
Proprioceptors (joint, muscle, touch)
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65
Flight feathers and tail feathers the common name and difference between primary and secondary
Remiges (flight feathers)
- Primaries - attached to the manus
- Secondaries - along the ulna, shorter than primaries and help to provide lift
- alular remiges - feathers arising from the alular digit
Retrices (tail feathers) - shape of a fan forming the tail in birds
- Function as rudder for turning
66
What gland is present in chickens what is the function in the bird
Uropygial gland
- Not present in all bird species
- Compound alveolar structure
- Function is to product water-proofing substance -> spreads to feathers via preening
- Tubules of the gland pass into two ducts and open on a single uropygial papilla
67
Pectoral limb what are the 3 digit called and the distal bones in the bird
1) alular
2) major
3) minor
- Tibiotarsus - proximal row of the tarsus is fused to the tibia
- Fibula - is reduced to a small spine fused to the tibiotarsus
- Tarsometatarsus - distal row of the tarsus is fused to the metatarsus
68
Sacral plexus of the chicken where present
Sacral plexus
- Ischiatic (sciatic) nerve origin from the sacral plexus
- Is in the intrarenal location
- The lumbar plexus and femoral and obturator nerves lie in contact with the dorsal surface of the kidney
○ Kidney disease that leads to swelling such as neoplasia can lead to pressure on these nerves resulting in lameness or leg paralysis
69
What are the 3 main divisions of the brain and regions within
1) Forebrain (Prosencephalon)
○ Telencephalon (cerebral hemispheres)
○ Diencephalon (thalamus, metathalamus, epithalamus, subthalamus and hypothalamus)
2) Midbrain (Mesencephalon)
○ Mesencephalon (tectum, tegmentum, cerebral peduncles)
3) Hindbrain (Rhombencephalon)
○ Metencephalon (dorsal: cerebellum and ventral: pons)
○ Myelencephalon (medulla oblongata)
70
What is the tentorium ossium and tentorium cerecelli and function
- A leaf of bone (the tentorium ossium) projects from the internal surface of the parietal bone and together with the membranous tentorium cerebelli partially separates the cerebrum from the cerebellum.
71
What is the ventricular system in the brain and where are the 4 ventricles
There are several interconnected cavities within the brain that together form the ventricular system.
1) Paired lateral ventricles - one within each verevral hemisphere
2) third ventricle - dorsoventrally oreintated ring
3) forth ventricle lies ventral to the cerebrullum and is on the dorsal aspect of hte pons and medulla
72
What is the reticular formation
A region of mixed grey and white matter located centrally throughout the length of the brainstem
73
What is gyri and sucli
The cerebral cortex may be convulted with raised gyri (singular: gyrus) separated by sulci (grooves - singular: sulcus).
74
What is the cruciate and lateral rhinal sulcus where located
Cruciate sulcus: a transverse groove between the frontal and parietal lobes
Lateral rhinal sulcus: separates the rhinencephalon (olfactory lobe) from the main part of cerebral hemispheres
Within the telencephalon (forebrain)
75
The hippocampus what part of the brain and where
```
THE FOREBRAIN (PROSENCEPHALON)
1. TELENCEPHALON
is a gyrus that lies deep to the piriform lobe and forms a semicircular structure that wraps around the dorsal and caudal aspects of the thalamus
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76
Basal nuclei of the telencephalon what is it and where located
- These accumulations of grey matter lie dorsal to the rhinencephalon, deep within the hemispheres.
77
What are the corpus callosum, the fornix, internal capsule, coronat radiata and crus cerebri and their locations
White matter of the telencephalon
1) corpus callosum (forms the roof of the lateral ventricles)
2) The fornix comprises the fibre tracts arising from the hippocampus from either side and lies ventral to the corpus callosum.
3) The internal capsule: comprises the projection fibres to and from the hemispheres and the fibres between the cortex and basal nuclei.
4) The corona radiata comprises the lateral and medial radiation of the internal capsule together with other cerebral white matter as it extends towards the cortex within each gyrus.
5) The crus cerebri on either side continue the internal capsule from each hemisphere into the brainstem.
78
Thalamus what region of the brain and where located
DIENCEPHALON
- Each side develops within the lateral walls of the third ventricle to bulge medially and connect with the other at the interthalamic adhesion, thereby reducing the 3rd ventricle to an encircling annular space.
79
Where are the lateral and medial geniculate bodies located within the brain
DIENCEPHALON
- On the caudodorsal aspect of the thalamus, it comprises the paired lateral and medial geniculate bodies
Medial geniculate body is more caudal
Lateral geniculate body is more rostral and lateral
80
Hypothalamus what region of the brain located and what important structures wtihin
- In the ventral wall of the 3rd ventricle medial to the subthalamus, it has the optic chiasm (two optical nerves cross over) of the optic nerves (CNII) on its ventral surface rostrally and it extends caudally to include the tuber cinereum and mamillary bodies.
- The tuber cinereum gives rise to the infundibulum that attaches the pituitary gland (hypophysis).
81
Oculomotor and trochlear nerve where located in the brain
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THE MIDBRAIN (MESENCEPHALON)
- only one that arises in the dorsal aspect of the brain stem) arise from the midbrain.
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82
What are the 3 regions of the midbrain (Mesencephalon) and important structures within
1) Tectum: Dorsal part of the midbrain comprised of paired rostral and caudal colliculi (rostral colliculus - visual) or auditory (caudal colliculus - auditory)
2) Tegmentum - red nucleus
3) Crus cerebri - white matter fibres on the ventral aspect
83
What is the red nucleus and where present
- The red nucleus (is red due to vascularity).
○ Outputs include the rubrospinal tract, an indirect corticospinal tract (extrapyramidal tract) and the main tract for voluntary movement in domestic species.
MIDBRAIN (MESENCEPHALON)
within the tegmentum
84
The hindbrain what is it called and what are the two structures within
Rhombencephalon
| = cerebellum + pons
85
What makes up the dorsal metencephalon and the 2 important zones with the surface ridges
The cerebeullum
the cerebellum is divided longitudinally into a midline elevation called the vermis and paired cerebellar hemispheres on either side
- The surface of the cerebellum has narrow ridges called folia separated by grooves called sulci.
86
what makes up the grey and white matter within the cerebeullum
Grey matter - cerebellar cortex
| White matter - medulla branching into the lobes named the arbor vitae (‘tree of life’).
87
How does the cerebellum communicate with the remainder of the CNS
via the three cerebellar peduncles:
1) Caudal cerebellar peduncle: both afferent and efferent fibres - connects cerebellum with vestibular apparatus, hindbrain and spinal cord.
2) Middle cerebellar peduncle: has afferent fibres only – continuation of transverse fibres of pons from pontine nuclei into cerebellum.
3) Rostral cerebellar peduncle: Mainly efferent fibres that project to motor control centres
88
The trigeminal nerve (CNV where does it emerge from in the brain
VENTRAL METENCEPHALON – THE PONS (beneath the cerebellum)
89
Pyramids of the brain, where is their location
MYELENCEPHALON – THE MEDULLA OBLONGATA
Ventral surface:
The pyramids extend from the rostral margin of the medulla oblongata to the level of the spinomedullary junction
90
Cranial nerves VI to XII where do they emerge from
from the medulla oblongata
