Practical 1

Question 1

What muscles attach the axial skeleton to the pectoral girdle?

Answer 1

Extrinsic shoulder muscles move the scapula and are divided into anterior and posterior divisions.

Anterior: attach rib cage to pectoral girdle
- pectoralis minor
- serratus anterior

Posterior:
- trapezius

Question 2

What muscles attach the axial skeleton to the humerous?

Answer 2

Anterior:
- pectoralis major: flexes the humerus

Posterior:
- latissimus dorsi: extends the humerus

Question 3

What muscles attach the pectoral girdle to the humerus?

Answer 3

Deltoid muscle: moves the humerus, stabilizes the glenohumeral joint, and abducts the arm.

Rotator Cuff Muscles: stabilize the glenohumeral joint
- subscapularis
- supraspinatus
- infraspinatus
- teres minor

Question 4

What muscles move the forearm?

Answer 4

The muscles that move the forearm do so at the elbow joint.

Biceps Brachii: flex the forearm and are powerful supinators

Triceps Brachii: extend the forearm

Question 5

What muscles move the wrist?

Answer 5

Anterior: flex the wrist and have a common origin on the medial epicondyle of the humerus.
- Flexor carpi radialis
- Flexor carpi ulnaris

Posterior: extend the wrist and have a common origin on the lateral epicondyle of the humerus.
- Extensor carpi radialis longus and brevis
- Extensor carpi ulnaris

Question 6

What does biceps mean?

Answer 6

Two heads

Question 7

What does triceps mean?

Answer 7

Three heads

Question 8

What does brachii mean?

Answer 8

arm

Question 9

What is the mystery muscle in the arm?

Answer 9

The mystery muscle is the palmaris longus that can have a bilateral occurrence, unilateral occurrence, or bilateral absence. It is superficial and inserts into connective tissues under the skin at the wrist. In surgery, it can be used as a graft for tendon.

Question 10

What muscles move the thigh?

Answer 10

Anterior: flex the thigh
- iliopsoas

Posterior: extend the thigh from the gluteal region
- gluteus maximus
- gluteus medius
- gluteus minimus

Question 11

What muscles move the leg?

Answer 11

Anterior:
- sartorius: crosses hip and knee to flex both joints
- quadriceps: solely act on the knee, extending it. These form the quadriceps tendon that insert on the patella which is connected to the tibia via the patellar ligament

Medial:
- adductors: move the thigh medially with minor movement of the leg

Posterior:
- hamstrings: extend the hip and flex the knee

Question 12

What muscles move the foot and ankle?

Answer 12

Anterior:
- tibialis anterior: extends the foot (dorsiflexion)

Lateral:
- peroneus (fibularis) longus: evert the foot

Posterior: flex the foot (plantar flexion) and insert to form the Achilles tendon
- gastrocnemius
- soleus
-

Question 13

What are the functions of the nervous system?

Answer 13

The nervous system controls voluntary and involuntary processes with three processes:

1) Sensory Input: gathers vital sensory information about external and internal environments with sensory nerves that detect input and travel through the body to communicate with other nerve cells.

2) Integration: incorporates simultaneous signals to create a picture of the environment.

3) Motor Output: appropriate response to input is sent by motor output signals through motor nerves that communicate from the brain and spinal cord to the skeletal, smooth, or cardiac muscle, causing them to relax or contract.

Question 14

What are the two subdivisions of the nervous system?

Answer 14

CNS: made of brain and spinal cord (control center)

PNS: composed of all nerves outside the brain and spinal cord (cranial, spinal, autonomic nervous system, and special sense organs)

Question 15

What are the different divisions of the PNS?

Answer 15

Efferent (Motor): relays information from the CNS to target cells

Afferent (Sensory): relays information to the CNS

Question 16

What is the difference between somatic and autonomic signalling?

Answer 16

Somatic: voluntary

Autonomic: involuntary

Question 17

What is the difference between sympathetic and parasympathetic response?

Answer 17

Sympathetic: fight-or-flight

Parasympathetic: rest-and-digest

Question 18

What are neurons?

Answer 18

Neurons are cells that are excitable and can generate and transmit rapid electrical signals to other neurons.

Dendrites: receive signal from other neurons and transfer it to the cell body.

Cell Body (soma): houses nucleus and organelles and functions to transfer electrical signals from the dendrites to the axon body.

Axon: carry signals from cell body to axon terminals where the signals are transferred to other neurons or organs.

Question 19

What are the classifications of neurons?

Answer 19

Neurons are classified based on the number of processes they have.

Pseudounipolar: one cellular process that splits into a dendrite and an axon

Bipolar: have two distinct cellular processes (sight/hearing)

Multipolar: have multiple dendrites and one axon (most common- motor neurons)

Question 20

What are supporting cells?

Answer 20

Supporting cells, known as neuroglia or glia, protect and support neurons, as well as aid in sending signals between neurons to improve communication. They do not generate nerve impulses.

Astrocytes: large star shaped cells in the CNS with numerous processes that communicate with neurons and blood vessels to maintain neural tissue integrity. (most abundant)

Microglia: small glial cells in the CNS that phagocytose pathogens and eliminate waste from other cells. (least common)

Ependymal: cuboidal and line cavities in the CNS for production, circulation, and monitoring of CSF.

Oligiodendrocytes: wrap around axons in the CNS to form myelin sheath with many processes.

Schwaan Cells: form myelin sheath around axons in the PNS

Question 21

What is myelin?

Answer 21

Myelin is a fatty coating around axons that appears white and insulates to increase the speed at which electrical signals travel.

The regions that are unmyelinated are nodes of Ranvier (neurofibril nodes).

Question 22

What is the cerebrum?

Answer 22

The cerebrum makes up the bulk of the brain with telencephalon and diencephalon.

Question 23

Discuss telencephalon.

Answer 23

Telencephalon interprets sensory signals, sends motor signals, and regulates decision making.

Cerebral Hemispheres:the cerebrum has the left and right hemispheres that are separated by the longitudinal fissure.

Cerebral Cortex: the outer layer of the cerebrum that appears a dark grey colour.

Sulci/Gyri: folding in the cerebrum increases surface area and functional capacity of neural tissue. Sulci are fissures and grooves that divide the brain into regions with different functions. Gyri are lumps and bumps that correspond to function. The precentral gyrus (motor cortex) sends motor output signals, while the postcentral gyrus (somatosensory cortex) receives sensory input (touch).

Lobes: have specific functions and are named based after the overlying skull bones.

Grey Matter: has nerve cell bodies, short interneurons, and glial cells in the cerebral cortex/inner brain areas.

White Matter: has bundles of nerve fibres and axons that make up tracts for neural communication.
- Association: communication in 1 hemisphere
- Commissural: communicate between 2 hemispheres (corpus callosum)
- Projection Fibres: communication between brain and spinal cord

Question 24

What is Lissencephaly?

Answer 24

a syndrome characterized by a lack of sulci and gyri that results in limited mental capacity, slow physical development, and life incompatibility after 10.

Question 25

Discuss diencephalon.

Answer 25

Diencephalon is deep to the telencephalon as the central core of the cerebrum, surrounded by the hemispheres.

It is responsible for sensory and motor relay into and out of the brain, as well as control of the autonomic nervous system.

Thalamus: has two bodies responsible for relaying sensory information, except smell, to areas of the brain.

Hypothalamus: connected to pituitary gland to control the release of hormones.

Question 26

What are the areas of the brainstem?

Answer 26

The brainstem connects the brain to the spinal cord and is essential for human functioning and survival with autonomic reflex centers and white matter tracts.

Midbrain: has large white matter tracts that make up the cerebral peduncles and two bumps known as superior/inferior colliculi.

Pons: has fibres connecting to the cerebellum for communication.

Medulla: continuous with the spinal cord

Question 27

What is the cerebellum?

Answer 27

The cerebellum sits under the occipital lobe and functions to coordinate motor activity.

Question 28

Discuss the meninges.

Answer 28

The meninges has 3 connective tissue membranes that protect CNS structures.

Dura Mater: most superficial and tough with a double layer of connective tissue that attaches to the skull. Makes the falx cerebri between hemispheres, tentorium cerebelli between the cerebrum/cerebellum, and the falx cerebelli at the midline of the cerebellum.

Arachnoid Mater: loosely covers the brain, creating the subarachnoid space filled with CSF and blood vessels.

Pia Mater: innermost layer, firmly attached to cerebral cortex.

Question 29

What are the ventricles?

Answer 29

Ventricles provide support and protection to the brain with 4 hollow spaces that are continuous with each other and the spinal cord, containing CSF.

Lateral: ‘c’ shaped spaces in hemispheres with a portion in each lobe.

Third: in the middle of the diencephalon, connected to the lateral ventricles with the interventricular foramina.

Fourth: sits between the pons/medulla and the cerebellum, connected to the third ventricle with the cerebral aqueduct. It is continuous with the central canal of the spinal cord and thee subarachnoid space.

Question 30

What is the flow direction of CSF?

Answer 30

lateral ventricles, interventricular foramen, third ventricle, cerebral aqueduct, fourth ventricle, subarachnoid space.

Question 31

Explain the spinal cord.

Answer 31

The spinal cord is located in the vertebral canal and is supported by the vertebral column to facilitate communication between the CNS and PNS through spinal nerves that exit the spinal cord to supply sensory and motor innervations to regions close to the level of exit

Question 32

What is the external topography of the spinal cord?

Answer 32

The spinal cord begins at the foramen magnum and extends to L2 (conus medullaris), then beyond where emerging axons (cauda equina) have thin strands of pia mater (filum terminale) that anchor the spinal cord to the sacrum and coccyx.

Regions of the spinal cord are named the same as the vertebrae, but since shorter, the regions are not located in the same areas.

Question 33

What are the spinal enlargements?

Answer 33

Spinal enlargements occur where the additional nerves exit the spinal cord to supply the limbs. (cervical - upper, lumbar - lower)

Question 34

What are the different levels of spinal injury?

Answer 34

C1-C3: limited movement of head/neck

C3-C4: head, neck, limited shoulder

C5: head, neck, shoulders, elbows, hands

C6-C7: head, neck, shoulders, arm, wrist

C8-T1: head, neck, shoulders, arm, wrist, fingers

T2-T6: impairment of legs

T7-T12: more function of legs

L: move hip and knees

Question 35

What are the meninges of the spinal cord?

Answer 35

Dura Mater: single layer of connective tissue with a fat-filled epidural space on the exterior.

Arachnoid Mater: makes subarachnoid space that is continuous with that of the brain and contains CSF.

Pia Mater: directly attached to spinal cord

Question 36

What is the internal topography of the spinal cord?

Answer 36

The spinal cord has an outer white matter and inner grey matter structure where the appearance is evident due to cell types.

Grey Matter: ventral horn carries motor information, while dorsal horn carries sensory information, and in between is the lateral horn which carries information from the sympathetic nervous system.

White Matter: has tracts of fibres that separate into anterior, lateral, and posterior funiculi.