Muscle Anatomy and Classification Quiz

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Questions and Answers

What is the primary action of the quadriceps femoris?

Abducts the thigh

Extends the knee (correct)

Flexes the knee

Dorsiflexes the foot

Which of the following muscles primarily aids in the abduction of the thigh?

Iliopsoas

Gluteus medius (correct)

Tibialis anterior

Gluteus maximus

What is the role of the tibialis anterior muscle?

Extends the toes (correct)

Flexes the hip joint

Plantar flexes the ankle joint

Lifts the heel

Which muscle group is primarily responsible for plantar flexing the foot?

Gastrocnemius Signup and view all the answers

What type of injury is characterized by pain in the crural region?

Shin splints Signup and view all the answers

What is the main advantage of slow-twitch muscle fibers?

Increased endurance Signup and view all the answers

What anatomical structure does the central nervous system consist of?

Brain and spinal cord Signup and view all the answers

What happens to muscle fibers when they are not used?

They go through atrophy Signup and view all the answers

Which structural characteristic is unique to cardiac muscle tissue?

Presence of intercalated discs Signup and view all the answers

Which factor increases the risk of muscle injuries?

Sudden intense stress Signup and view all the answers

What type of muscle cell structure lacks striations?

Smooth muscle Signup and view all the answers

The gluteus maximus primarily performs which two actions?

Extends and abducts the thigh Signup and view all the answers

What is the primary cause of muscular dystrophy?

Defective dystrophin gene Signup and view all the answers

Which connective tissue surrounds a muscle fascicle?

Perimysium Signup and view all the answers

How does resistance exercise affect muscle size?

Stimulates hypertrophy of muscle fibers Signup and view all the answers

What is characteristic of smooth muscle that can classify its control mechanisms?

Can be multiunit or unitary Signup and view all the answers

What type of joint is primarily responsible for the rotation of a bone on its axis?

Pivot joint Signup and view all the answers

Which movement decreases the angle between two body parts?

Flexion Signup and view all the answers

What feature is unique to the shoulder joint compared to other joints?

Ball-and-socket structure Signup and view all the answers

Which is NOT a type of synovial joint?

Ellipsoidal Signup and view all the answers

Which term describes the movement of a body part toward the midline?

Adduction Signup and view all the answers

What is the primary cause of osteoarthritis?

Wear-and-tear Signup and view all the answers

Which joint is classified as a hinge joint?

Elbow joint Signup and view all the answers

Which type of joint allows for the greatest range of motion?

Ball-and-socket joint Signup and view all the answers

What is the primary role of cerebrospinal fluid (CSF)?

Providing buoyancy, protection, and chemical stability Signup and view all the answers

Which structures produce cerebrospinal fluid within the brain ventricles?

Choroid plexus Signup and view all the answers

Which of the following accurately describes the anatomy of the medulla oblongata?

Extends from the pons to the foramen magnum of the skull Signup and view all the answers

What is the role of the arachnoid granulations in the cerebrospinal fluid system?

They absorb cerebrospinal fluid back into the bloodstream. Signup and view all the answers

Which region of the brain is referred to as the 'sensory gateway to the cerebral cortex'?

Thalamus Signup and view all the answers

What identifies the pons in terms of its physical characteristics?

It creates a large bulge from the anterior aspect. Signup and view all the answers

What is a major consequence of degeneration in the substantia nigra?

Parkinson's Disease Signup and view all the answers

Which layer of the meninges is described as a delicate inner layer?

Pia mater Signup and view all the answers

What type of synapse connects an axon to a dendrite?

Axodendritic synapse Signup and view all the answers

Which type of circuitry involves multiple inputs converging onto a single neuron?

Converging circuit Signup and view all the answers

What anatomical feature runs down the center of the spinal cord and contains cerebrospinal fluid?

Central canal Signup and view all the answers

Which statement best describes gray matter in the spinal cord?

Has two dorsal horns and two ventral horns Signup and view all the answers

What is the main function of ascending tracts in the spinal cord?

Carry sensory information to the brain Signup and view all the answers

What layer of connective tissue wraps an entire nerve?

Epineurium Signup and view all the answers

Which of the following structures is NOT part of the cross-sectional anatomy of the spinal cord?

Dorsal root ganglion Signup and view all the answers

What type of synapse connects an axon directly to another axon?

Axoaxonic Signup and view all the answers

Study Notes

Connective Tissues Surrounding Muscles

Epimysium: Encases the entire muscle
Perimysium: Surrounds fascicles (bundles of muscle fibers)
Endomysium: Wraps individual muscle fibers

Muscle Classification

Fusiform muscles: Thick in the middle, tapered at the ends
Parallel muscles: Uniform width, fascicles aligned

Muscles Acting on the Thigh

Anterior muscles of the thigh: Quadriceps femoris (extends the knee)
- Rectus femoris
- Vastus lateralis
- Vastus medialis
- Vastus intermedius
Posterior gluteal muscles:
- Gluteus maximus (extends and abducts the thigh)
- Gluteus medius (abducts and medially rotates the thigh)
- Gluteus minimus (abducts and medially rotates the thigh)

Muscles Acting on the Leg

Anterior compartment muscles: Dorsiflex the foot and extend the toes
Posterior compartment muscles: Plantar flex the foot and flex the toes

Muscle Attachments and Innervation

Quadriceps femoris: Attaches to the anterior inferior iliac spine and tibial tuberosity
Hamstrings: Attach to the ischial tuberosity and bones of the leg
Tibialis anterior: Attaches to the lateral condyle of the tibia and medial cuneiform
Gastrocnemius: Attaches to the femur and calcaneus via the Achilles tendon

Muscle Injuries

Pitcher’s arm: Inflammation at the attachments of the wrist flexors
Blocker’s arm: Abnormal calcification in the lateral margin of the forearm
Shin splints: Pain in the crural region caused by tendinitis of the tibialis posterior and inflammation of the periosteum
Tennis elbow: Inflammation at the attachment of extensor carpi muscles that attach to the lateral epicondyle

Nervous System

Functions: Sensory perception, integration, and motor planning
Subdivisions:
- Central nervous system (CNS): Brain and spinal cord
- Peripheral nervous system (PNS): Nerves and ganglia

Synapses

Axodendritic synapse: Axon to dendrite
Axosomatic synapse: Axon to neurosoma (cell body)
Axoaxonic synapse: Axon to axon

Spinal Cord

Functions: Transmits signals between the brain and the body, coordinates reflexes
Surface Anatomy:
- Regions: Cervical, Thoracic, Lumbar, Sacral
- Enlargements: Cervical, Lumbosacral
- Medullary cone: Conical end of the spinal cord
- Cauda equina: Collection of nerve roots at the end of the spinal cord
- Terminal filum: Fibrous extension from the conus medullaris
Cross-Sectional Anatomy:
- Fissure/Sulcus: Anterior median fissure, Posterior median sulcus
- Central canal: Runs down the center, Contains cerebrospinal fluid (CSF)
Gray matter: Contains very few myelinated axons, Has two posterior (dorsal) horns and two anterior (ventral) horns
White matter: Contains myelinated axons
- Columns (funiculi): Posterior (dorsal), lateral, and anterior (ventral)
  - Tracts (fasciculi): Located within the columns
Ascending Tracts: Carry sensory info to the brain
Descending Tracts: Carry motor info from the brain

Nerves and Ganglia

Nerve: Several axons wrapped by connective tissue
- Epineurium: Wraps the entire nerve
- Perineurium: Wraps a fascicle of axons
Ganglion: Collection of neuron cell bodies outside the CNS

Brain Meninges

Dura Mater: Tough, outer layer, epidural space
Arachnoid Mater: Transparent, middle layer, contains CSF, arachnoid granulations
Pia Mater: Delicate, inner layer

Ventricles and Cerebrospinal Fluid (CSF)

Ventricles: Fluid-filled chambers in the brain
- Lateral ventricles (2)
- Third ventricle (1)
- Fourth ventricle (1)
- Central Canal of Spinal Cord
CSF: Clear, colorless liquid
- Production: By choroid plexus (ependymal cells) within the ventricles
- Flow: Within ventricles, down canals, and within subarachnoid space
- Absorption: Back into blood at superior sagittal sinus by arachnoid granulations
Functions: Provides buoyancy, protection, and chemical stability for the brain

Brainstem

Components:
- Midbrain
- Pons
- Medulla oblongata
Pons:
- Anterior aspect: Contains longitudinal and transverse fascicles
- Posterior aspect: Contains peduncles that attach to cerebellum
Midbrain:
- Tectum (posterior aspect): Tectal plate (corpora quadrigemina) - four bulges consisting of superior and inferior colliculi
Medulla oblongata:
- Location: Extends from the pons to the foramen magnum
Functions:
- Pons: Contains tracts between the spinal cord and brain/cerebellum
- Midbrain: Substantia nigra (degenerates leading to Parkinson’s)
- Medulla oblongata: Contains cardiac center, vasomotor center, respiratory center

Diencephalon

Components:
- Thalamus: "Sensory gateway to the cerebral cortex." All sensory input except for smell goes through here.
- Hypothalamus: Controls autonomic functions (heart rate, body temperature, hunger, thirst), endocrine control (pituitary gland)
- Epithalamus: Contains pineal gland (secretes melatonin)

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Description

Test your knowledge on the connective tissues surrounding muscles, the classification of different muscle types, and the muscles acting on both the thigh and leg. This quiz covers important structures including epimysium, perimysium, and key muscle groups like the quadriceps and gluteal muscles.