Class 11 : Biology (In English) – Lesson 17: Locomotion and Movement

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On June 21, 2025

EXPLANATION & SUMMARY

🌱✨ Introduction
🧠 Movement is one of the fundamental characteristics of living organisms. It refers to a change in body position or a part of the body.
⚙️ Locomotion is a special type of movement that results in a change of location of the organism — like walking, running, flying, or swimming.
🌿 In plants, movement is usually growth-oriented, while in animals, locomotion helps in finding food, shelter, mates, and escaping predators.
💡 Concept:
Movement = any displacement (can be internal or external)
Locomotion = displacement of the entire body
All locomotions are movements, but not all movements are locomotions

🧬 Types of Movement
Organisms exhibit three major types of movements:
1️⃣ Amoeboid Movement
Seen in amoeba, WBCs
Achieved by pseudopodia (cytoplasmic extensions)
Involves cytoplasmic streaming and actin filament rearrangement
✏️ Example: Movement of macrophages during phagocytosis.

2️⃣ Ciliary Movement
Uses tiny hair-like cilia
Found in paramecium, tracheal epithelium, fallopian tubes
Coordinated beating moves fluids or the entire organism
💡 In humans:
➡️ Respiratory tract – clears mucus
➡️ Oviduct – moves ovum toward uterus

3️⃣ Muscular Movement
Involves contraction and relaxation of muscle fibers
Responsible for locomotion in higher animals
Works under neural control
✏️ Seen in limbs, heart, alimentary canal.

🦴 Human Muscular System
🧠 Muscles are specialized contractile tissues derived from mesoderm.
📘 Classified into three main types:

🟢 1️⃣ Skeletal (Striated / Voluntary) Muscles
Attached to bones via tendons
Multinucleated, striated (light and dark bands)
Voluntary control
Function: locomotion, posture, body movement
💪 Examples: Biceps, triceps, quadriceps

🔵 2️⃣ Smooth (Unstriated / Involuntary) Muscles
Found in walls of visceral organs (stomach, intestine, blood vessels)
Uninucleated, non-striated
Involuntary control
Function: movement of food, vessel constriction

🔴 3️⃣ Cardiac Muscles
Found only in heart ❤️
Striated, branched, uninucleated
Involuntary, rhythmic contraction
Function: pumps blood continuously
💡 Concept: All muscle contractions are powered by ATP and regulated by calcium ions (Ca²⁺).

⚙️ Structure of Skeletal Muscle

🧬 Muscle → bundles of muscle fascicles → muscle fibers (cells) → myofibrils
Each myofibril shows alternating dark (A band) and light (I band), giving striated appearance.
📘 Sarcomere = structural & functional unit of contraction
Bound by Z-lines

🔹 Components of a Sarcomere

Band Description
A band Dark band (myosin + overlap with actin)
I band Light band (only actin)
H zone Center of A band (only myosin)
M line Midline of sarcomere
Z line Boundary between sarcomeres
💡 During contraction:
Sarcomere length decreases
I band & H zone shorten, A band constant

🧠 Sliding Filament Theory
🧪 Proposed by Huxley and Niedergerke
⚙️ Explains muscle contraction as sliding of actin filaments over myosin filaments.
🌀 Steps:
1️⃣ Impulse from motor neuron → release of Ca²⁺ from sarcoplasmic reticulum
2️⃣ Ca²⁺ binds troponin, exposes binding sites on actin
3️⃣ Myosin head attaches to actin → forms cross bridge
4️⃣ ATP hydrolysis → myosin pulls actin inward (power stroke)
5️⃣ New ATP breaks cross bridge → cycle repeats
💡 Energy: ATP
💡 Ions: Ca²⁺, Mg²⁺
✏️ Result: Shortening of sarcomere = contraction.

🧬 Neuromuscular Junction

📘 Synapse between motor neuron and muscle fiber
🧠 Impulse → releases acetylcholine (ACh) into synaptic cleft
➡️ Triggers depolarization → contraction
⚙️ AChE (acetylcholinesterase) breaks down ACh to stop contraction.

💪 Types of Muscle Contractions

1️⃣ Isotonic – muscle shortens, movement occurs
2️⃣ Isometric – tension changes, length constant
3️⃣ Tetanic – sustained contraction from rapid stimuli
✏️ Example: Holding weight → isometric; lifting → isotonic.

🦴 Skeletal System
🦴 Framework of bones and cartilage that supports body and aids movement.
📘 Human skeleton:
Axial skeleton – skull, vertebral column, ribs, sternum
Appendicular skeleton – limbs and girdles
🧠 Total bones: 206 in adult

🌿 Axial Skeleton (80 bones)

Skull: 22 bones (8 cranial + 14 facial)
Vertebral column: 26 vertebrae
Ribs: 12 pairs
Sternum: 1
💡 Protects brain, spinal cord, heart, lungs.

💪 Appendicular Skeleton (126 bones)
Pectoral girdle: 4
Pelvic girdle: 2
Limbs: 60 (upper) + 60 (lower)
⚙️ Enables movement and locomotion.

🦵 Limb Bones
🖐️ Upper Limb
Humerus → Radius + Ulna → Carpals → Metacarpals → Phalanges
🦶 Lower Limb
Femur → Tibia + Fibula → Tarsals → Metatarsals → Phalanges
✏️ Longest bone: Femur
💡 Strongest joint: Knee joint

🔩 Joints
📘 Articulation = point of contact between bones
Types (Structural basis):
1️⃣ Fibrous (Immovable) – skull sutures
2️⃣ Cartilaginous (Partially movable) – vertebral joints
3️⃣ Synovial (Freely movable) – limbs (shoulder, knee)
🧪 Synovial joint features:
Synovial fluid (lubrication)
Capsule, ligaments
Articular cartilage
💡 Examples:
Ball & socket: shoulder

Hinge: elbow, knee

Pivot: neck (atlas-axis)
Gliding: wrist

Saddle: thumb
Condyloid: fingers

⚙️ Disorders of Muscles and Bones
1️⃣ Myasthenia gravis – autoimmune; blocks ACh receptors → weakness
2️⃣ Muscular dystrophy – genetic; degeneration of muscles

3️⃣ Tetanus – sustained contraction due to toxin
4️⃣ Osteoporosis – bone thinning (↓ calcium, estrogen)
5️⃣ Arthritis – inflammation of joints
6️⃣ Gout – uric acid accumulation in joints
7️⃣ Fracture – bone breakage
💡 Proper nutrition, exercise, and posture maintain skeletal health.

🌍 Importance of Locomotion
🧠 Enables interaction with environment
⚡ Supports feeding, reproduction, protection
🧬 Maintains organism survival
🌿 In humans, essential for daily activities, sports, and circulation (muscle pump effect)

🌍 Why This Lesson Matters
💪 Explains how the body moves and mechanics of muscles
🧠 Connects anatomy and physiology
⚙️ Foundation for sports medicine, orthopedics, neurobiology
🌍 Highlights importance of calcium, exercise, and posture

📝 Quick Recap
🧠 Movement = body part displacement
🏃 Locomotion = movement + location change
💪 Muscles: skeletal, smooth, cardiac
⚙️ Sarcomere = unit of contraction
🧬 Sliding filament theory: actin slides over myosin
🧠 Ca²⁺ + ATP essential for contraction
🦴 Skeleton: 206 bones; axial + appendicular
🔩 Joints: fibrous, cartilaginous, synovial
⚠️ Disorders: Myasthenia, osteoporosis, arthritis
🌍 Movement vital for life and activity

📘 Summary
Locomotion and movement form the basis of animal activity. Movements can be amoeboid, ciliary, or muscular. In humans, skeletal muscles enable locomotion through contraction based on the sliding filament theory. The skeletal system, with bones and joints, provides structure, support, and leverage. The nervous system and ions like calcium coordinate contraction. Joints permit various movements, while disorders such as arthritis and osteoporosis impair mobility. This system ensures organisms interact with their environment, sustain posture, and perform essential functions.

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QUESTIONS FROM TEXTBOOK

🔵 Question 1. Draw the diagram of a sarcomere of skeletal muscle showing different regions.
🟢 Answer:
🧠 A sarcomere is the functional unit of a myofibril, extending between two Z-lines.
🧬 Regions:
A-band: Dark band with both actin and myosin.
I-band: Light band with actin only.
H-zone: Central part of A-band with myosin only.
M-line: Middle line of H-zone.
Z-line: Boundary of sarcomere.
💡 During contraction: I-band and H-zone shorten; A-band remains constant.
✏️ (Diagram to be drawn showing Z-line, A-band, I-band, H-zone, M-line)

🔵 Question 2. Define sliding filament theory of muscle contraction.
🟢 Answer:
⚙️ Sliding Filament Theory:
Explains muscle contraction due to sliding of thin (actin) filaments over thick (myosin) filaments.
Filaments do not change length, sarcomere shortens.
💡 Powered by ATP hydrolysis and Ca²⁺ ions, forming cross-bridges between actin and myosin.
✔️ Result: Shortening of muscle fibre → contraction.

🔵 Question 3. Describe the important steps in muscle contraction.
🟢 Answer:
🧬 Steps:
Impulse from motor neuron → releases acetylcholine → depolarises sarcolemma.
Ca²⁺ ions released from sarcoplasmic reticulum.
Ca²⁺ binds troponin, shifting tropomyosin, exposing binding sites on actin.
Myosin head binds actin → cross-bridge forms.
ATP hydrolysis → power stroke → filaments slide.
ATP binding detaches myosin head → next cycle begins.
Ca²⁺ reabsorbed → relaxation.
✔️ Requires ATP and Ca²⁺.

🔵 Question 4. Write true or false. If false, change the statement so that it is true.
🟢 Answer:
(a) Actin is present in thin filament — ✔️ True
(b) H-zone of striated muscle fibre represents both thick and thin filaments — ❌ False
➡️ Correct: H-zone has only thick (myosin) filaments.
(c) Human skeleton has 206 bones — ✔️ True
(d) There are 11 pairs of ribs in man — ❌ False
➡️ Correct: There are 12 pairs of ribs.
(e) Sternum is present on the ventral side of the body — ✔️ True

🔵 Question 5. Write the difference between:
🟢 Answer:
(a) 🌿 Actin and Myosin
Feature Actin Myosin
Type Thin filament Thick filament
Composition Actin, tropomyosin, troponin Myosin protein
Function Slides over myosin Cross-bridge formation
(b) 🌸 Red and White muscles
Feature Red Muscle White Muscle
Myoglobin High Low
Mitochondria Many Few
Endurance High Low
Fatigue Resistant Quickly fatigued
(c) 🦴 Pectoral and Pelvic girdle
Feature Pectoral Pelvic
Function Supports forelimbs Supports hindlimbs
Bones Clavicle, scapula Ilium, ischium, pubis
Location Upper trunk Lower trunk

🔵 Question 6. Match Column I with Column II:
Column I Column II
(a) Smooth muscle (iv) Involuntary
(b) Tropomyosin (ii) Thin filament
(c) Red muscle (i) Myoglobin
(d) Skull (iii) Sutures
✔️ Correct matches: (a)-(iv), (b)-(ii), (c)-(i), (d)-(iii)

🔵 Question 7. What are the different types of movements exhibited by the cells of human body?
🟢 Answer:
🌿 Types:
Amoeboid movement – leucocytes, macrophages.
Ciliary movement – lining of trachea, fallopian tubes.
Muscular movement – skeletal muscles, limbs.
✔️ All help in locomotion and internal transport.

🔵 Question 8. How do you distinguish between a skeletal muscle and a cardiac muscle?
🟢 Answer:
Feature Skeletal Muscle Cardiac Muscle
Control Voluntary Involuntary
Nucleus Multinucleated Single nucleus
Intercalated discs Absent Present
Fatigue Rapid Never fatigues
Function Body movement Pumping of blood

🔵 Question 9. Name the type of joint between the following:
🟢 Answer:
(a) Atlas/Axis → Pivot joint
(b) Carpal/Metacarpal of thumb → Saddle joint
(c) Between phalanges → Hinge joint
(d) Femur/Acetabulum → Ball and socket joint
(e) Between cranial bones → Sutures (fibrous joint)
(f) Between pubic bones in pelvic girdle → Cartilaginous joint

🔵 Question 10. Fill in the blank spaces:
🟢 Answer:
(a) All mammals (except a few) have 7 cervical vertebrae.
(b) The number of phalanges in each limb of human is 14.
(c) Thin filament of myofibril contains 2 ‘F’ actins and two other proteins namely tropomyosin and troponin.
(d) In a muscle fibre, Ca²⁺ is stored in sarcoplasmic reticulum.
(e) 11th and 12th pairs of ribs are called floating ribs.
(f) The human cranium is made of 8 bones.

(CBSE MODEL QUESTIONS PAPER)

ESPECIALLY MADE FROM THIS LESSON ONLY

🔴 Question 1:
Which protein is responsible for muscle contraction?
🔴1️⃣ Keratin
🟢2️⃣ Actin and Myosin
🟡3️⃣ Collagen
🔵4️⃣ Elastin
🟢 Answer: 2️⃣ Actin and Myosin

🔴 Question 2:
Functional unit of muscle contraction is —
🔴1️⃣ Myofibril
🟢2️⃣ Sarcomere
🟡3️⃣ Muscle fibre
🔵4️⃣ Fascicle
🟢 Answer: 2️⃣ Sarcomere

🔴 Question 3:
Which of the following shows amoeboid movement in humans?
🔴1️⃣ Muscle cells
🟢2️⃣ Leucocytes
🟡3️⃣ RBCs
🔵4️⃣ Neurons
🟢 Answer: 2️⃣ Leucocytes

🔴 Question 4:
Which joint allows movement in all directions?
🔴1️⃣ Hinge joint
🟢2️⃣ Ball and socket joint
🟡3️⃣ Pivot joint
🔵4️⃣ Saddle joint
🟢 Answer: 2️⃣ Ball and socket joint

🔴 Question 5:
Which part of the myofibril disappears during contraction?
🔴1️⃣ A band
🟢2️⃣ H zone
🟡3️⃣ I band
🔵4️⃣ Z line
🟢 Answer: 2️⃣ H zone

🔴 Question 6:
Which ion triggers muscle contraction?
🔴1️⃣ Na⁺
🟢2️⃣ Ca²⁺
🟡3️⃣ K⁺
🔵4️⃣ Mg²⁺
🟢 Answer: 2️⃣ Ca²⁺

🔴 Question 7:
The longest bone in human body is —
🔴1️⃣ Humerus
🟢2️⃣ Femur
🟡3️⃣ Tibia
🔵4️⃣ Radius
🟢 Answer: 2️⃣ Femur

🔴 Question 8:
Which connective tissue joins muscle to bone?
🔴1️⃣ Ligament
🟢2️⃣ Tendon
🟡3️⃣ Cartilage
🔵4️⃣ Fascia
🟢 Answer: 2️⃣ Tendon

🔴 Question 9:
The number of bones in adult human skeleton is —
🔴1️⃣ 200
🟢2️⃣ 206
🟡3️⃣ 210
🔵4️⃣ 208
🟢 Answer: 2️⃣ 206

🔴 Question 10:
Which enzyme hydrolyses ATP during muscle contraction?
🔴1️⃣ ATP synthase
🟢2️⃣ Myosin ATPase
🟡3️⃣ Actinase
🔵4️⃣ Kinase
🟢 Answer: 2️⃣ Myosin ATPase

🔴 Question 11:
Define locomotion.
🟢 Answer:
The voluntary movement of an organism from one place to another is called locomotion (e.g., walking, running).

🔴 Question 12:
Name the three types of muscles in the human body.
🟢 Answer:
1️⃣ Skeletal (Striated) — Voluntary, multinucleated
2️⃣ Smooth (Unstriated) — Involuntary, single nucleus
3️⃣ Cardiac — Involuntary, striated, branched

🔴 Question 13:
Define movement and locomotion. Differentiate between them.
🟢 Answer:
Movement: Change in position of a body part (can be voluntary or involuntary).
Locomotion: Voluntary movement of the entire organism from one place to another.
Feature Movement Locomotion
Scope May be of a part Whole body
Voluntary Can be voluntary/involuntary Always voluntary
Example Beating of heart Walking, running
💡 All locomotions are movements, but all movements are not locomotions.

🔴 Question 14:
What are the different types of movements in animals?
🟢 Answer:
1️⃣ Amoeboid movement:
– In leucocytes; uses pseudopodia.
2️⃣ Ciliary movement:
– In respiratory tract & fallopian tubes; uses cilia.
3️⃣ Muscular movement:
– Due to muscle contraction; e.g., walking, running.
💡 Human body shows all three types of movement.

🔴 Question 15:
Explain the structure of a sarcomere.
🟢 Answer:
Definition: Structural & functional unit of myofibril (between two Z-lines).
Components:
1️⃣ A band (dark): Contains thick filament (myosin).
2️⃣ I band (light): Contains thin filament (actin).
3️⃣ H zone: Central part with only myosin.
4️⃣ Z line: Boundary of sarcomere.
💡 During contraction, H zone shortens, A band remains same.

🔴 Question 16:
Describe the chemical events of muscle contraction.
🟢 Answer:
1️⃣ Nerve impulse → releases Ca²⁺ from sarcoplasmic reticulum.
2️⃣ Ca²⁺ binds to troponin, exposing binding sites on actin.
3️⃣ Myosin head binds to actin → forms cross bridge.
4️⃣ ATP hydrolysis by myosin ATPase → energy for sliding.
5️⃣ Actin filaments slide → sarcomere shortens.
✅ Relaxation when Ca²⁺ returns to SR.

🔴 Question 17:
List the functions of skeleton.
🟢 Answer:
1️⃣ Support: Framework maintaining body shape.
2️⃣ Protection: Vital organs (skull–brain, ribs–heart).
3️⃣ Movement: Bones act as levers with muscles.
4️⃣ Haemopoiesis: Bone marrow forms blood cells.
5️⃣ Mineral storage: Ca, P.
💡 Total 206 bones in adult human.

🔴 Question 18:
Differentiate between axial and appendicular skeleton.
🟢 Answer:
Feature Axial Appendicular
Components Skull, vertebral column, ribs, sternum Limbs & girdles
Bones 80 126
Function Protection & support Movement
Example Ribs Humerus
💡 Together form complete skeleton.

🔴 Question 19:
What are synovial joints? Name their types.
🟢 Answer:
Definition: Freely movable joints with synovial fluid.
Types:
1️⃣ Ball & Socket – Shoulder, hip.
2️⃣ Hinge – Elbow, knee.
3️⃣ Pivot – Atlas-axis joint.
4️⃣ Gliding – Carpals.
5️⃣ Saddle – Thumb joint.
💡 Enable various types of movements.

🔴 Question 20:
Write the differences between red and white muscles.
🟢 Answer:
Feature Red Muscles White Muscles
Myoglobin High Low
Mitochondria Many Few
Endurance High Low
Colour Dark red Pale
Function Sustained activity Quick action
💡 Red = aerobic; White = anaerobic.

🔴 Question 21:
Describe the structure of a typical vertebra.
🟢 Answer:
Components:
1️⃣ Centrum: Main body.
2️⃣ Neural canal: For spinal cord.
3️⃣ Processes: Transverse and spinous for muscle attachment.
Types: Cervical (7), Thoracic (12), Lumbar (5).
💡 Vertebral column provides support & protection.

🔴 Question 22:
List the three types of muscles with their properties.
🟢 Answer:
Type Control Striation Nucleus Function
Skeletal Voluntary Striated Multi Locomotion
Smooth Involuntary Unstriated Single Internal organs
Cardiac Involuntary Striated Single Heartbeat
💡 Cardiac muscles are myogenic & fatigue-resistant.

🔴 Question 23:
Explain the sliding filament theory of muscle contraction.
🟢 Answer:
Concept: Muscle contraction occurs due to sliding of thin (actin) filaments over thick (myosin) filaments.
Steps:
1️⃣ Impulse: Nerve impulse releases Ca²⁺ from sarcoplasmic reticulum.
2️⃣ Exposure: Ca²⁺ binds to troponin, shifts tropomyosin, exposes binding sites on actin.
3️⃣ Cross-bridge: Myosin heads attach to actin → form cross-bridges.
4️⃣ Power stroke: Myosin heads use ATP to pull actin inward → sarcomere shortens.
5️⃣ Detachment: ATP binds again → myosin detaches; cycle repeats.
💡 A band constant, I band & H zone shorten → muscle contracts.

🔴 Question 24:
Describe the structure of human skeleton.
🟢 Answer:
Divisions:
1️⃣ Axial skeleton (80 bones): Skull (22), vertebral column (26), ribs (24), sternum (1), hyoid (1), ear ossicles (6).
2️⃣ Appendicular skeleton (126 bones): Limbs & girdles (pectoral and pelvic).
Functions:
✔️ Support and protection of organs.
✔️ Locomotion with muscles.
✔️ Haemopoiesis in bone marrow.
✔️ Mineral storage (Ca, P).
💡 Total = 206 bones in adult human.

🔴 Question 25:
Explain the structure of a typical myofibril.
🟢 Answer:
Myofibril: Cylindrical structure inside muscle fibre.
Bands:
1️⃣ A band (dark): Thick myosin filaments.
2️⃣ I band (light): Thin actin filaments.
3️⃣ H zone: Central part with only myosin.
4️⃣ Z line: Border between sarcomeres.
Sarcomere: Segment between two Z-lines = functional unit.
💡 Contraction: actin slides over myosin → sarcomere shortens.

🔴 Question 26:
Describe the events of muscle contraction and relaxation.
🟢 Answer:
Contraction:
1️⃣ Impulse from motor neuron → Ca²⁺ released.
2️⃣ Ca²⁺ binds troponin → exposes actin sites.
3️⃣ Myosin binds actin → cross-bridge forms.
4️⃣ ATP hydrolysis → power stroke → filaments slide.
Relaxation:
1️⃣ Ca²⁺ pumped back to sarcoplasmic reticulum.
2️⃣ Tropomyosin covers actin sites.
3️⃣ Cross-bridges detach → muscle returns to rest.
💡 Energy: Provided by ATP; lack of ATP → rigor mortis.

🔴 Question 27:
Explain the structure and functions of synovial joint.
🟢 Answer:
Structure:
– Ends of bones covered with cartilage.
– Enclosed by joint capsule lined with synovial membrane.
– Synovial fluid lubricates and reduces friction.
Functions:
✔️ Free movement in various directions.
✔️ Shock absorption.
✔️ Stability and flexibility.
Examples: Shoulder (ball & socket), elbow (hinge).

🔴 Question 28:
Describe the disorders of the muscular and skeletal system.
🟢 Answer:
1️⃣ Myasthenia gravis: Autoimmune; weak neuromuscular transmission.
2️⃣ Tetany: Low Ca²⁺ → spasms.
3️⃣ Muscular dystrophy: Degeneration of muscles.
4️⃣ Arthritis: Inflammation of joints.
5️⃣ Osteoporosis: Bone weakening due to low calcium.
💡 Balanced diet & exercise prevent many disorders.

🔴 Question 29:
Explain the types and functions of joints in the human body.
🟢 Answer:
1️⃣ Fibrous joints: Immovable (e.g., skull sutures).
2️⃣ Cartilaginous joints: Slightly movable (e.g., vertebrae).
3️⃣ Synovial joints: Freely movable; types:
– Ball & socket (hip)
– Hinge (elbow)
– Pivot (neck)
– Gliding (carpals)
– Saddle (thumb)
💡 Functions: Movement, flexibility, shock absorption.

🔴 Question 30:
Describe the appendicular skeleton and its role.
🟢 Answer:
Components (126 bones):
1️⃣ Pectoral girdle (4): Clavicle & scapula.
2️⃣ Pelvic girdle (2): Hip bones.
3️⃣ Limbs (120):
– Upper limb: Humerus, radius, ulna, carpals, metacarpals, phalanges.
– Lower limb: Femur, tibia, fibula, tarsals, metatarsals, phalanges.
Functions:
✔️ Locomotion and manipulation.
✔️ Attachment of muscles.
✔️ Protection (pelvis → reproductive organs).

NEET QUESTIONS FROM THIS LESSON

🔵 Q1. The contractile protein of muscle involved in shortening of sarcomere is
🟡 A. Myosin
🟡 B. Actin
🟡 C. Troponin
🟡 D. Tropomyosin
🟢 Answer: B. Actin
📅 NEET 2019

🔵 Q2. The functional unit of a striated muscle fibre is
🟡 A. Sarcolemma
🟡 B. Sarcomere
🟡 C. Myofibril
🟡 D. Cross bridge
🟢 Answer: B. Sarcomere
📅 AIPMT 2014

🔵 Q3. The cross bridges in muscle contraction are formed between
🟡 A. Actin and myosin
🟡 B. Myosin and troponin
🟡 C. Troponin and tropomyosin
🟡 D. Actin and tropomyosin
🟢 Answer: A. Actin and myosin
📅 NEET 2017

🔵 Q4. Sliding filament theory was proposed by
🟡 A. Huxley and Niedergerke
🟡 B. Darwin and Lamarck
🟡 C. Watson and Crick
🟡 D. Calvin and Benson
🟢 Answer: A. Huxley and Niedergerke
📅 AIPMT 2013

🔵 Q5. The smallest contractile unit of muscle is
🟡 A. Myofibril
🟡 B. Sarcomere
🟡 C. Myosin head
🟡 D. Z line
🟢 Answer: B. Sarcomere
📅 NEET 2018

🔵 Q6. Which ion is essential for muscle contraction?
🟡 A. Na⁺
🟡 B. K⁺
🟡 C. Ca²⁺
🟡 D. Mg²⁺
🟢 Answer: C. Ca²⁺
📅 AIPMT 2012

🔵 Q7. During muscle contraction, ATP attaches to
🟡 A. Actin
🟡 B. Myosin head
🟡 C. Troponin
🟡 D. Tropomyosin
🟢 Answer: B. Myosin head
📅 NEET 2016

🔵 Q8. The H-zone in the skeletal muscle fibre is the zone of
🟡 A. Actin filaments only
🟡 B. Myosin filaments only
🟡 C. Both actin and myosin
🟡 D. Z line
🟢 Answer: B. Myosin filaments only
📅 AIPMT 2015

🔵 Q9. The synovial fluid is present in
🟡 A. Fixed joints
🟡 B. Hinge joints
🟡 C. Synovial joints
🟡 D. Suture joints
🟢 Answer: C. Synovial joints
📅 NEET 2014

🔵 Q10. Which joint allows movement in all directions?
🟡 A. Hinge joint
🟡 B. Pivot joint
🟡 C. Ball-and-socket joint
🟡 D. Gliding joint
🟢 Answer: C. Ball-and-socket joint
📅 AIPMT 2013

🔵 Q11. The connective tissue surrounding a muscle fibre is
🟡 A. Sarcolemma
🟡 B. Endomysium
🟡 C. Epimysium
🟡 D. Perimysium
🟢 Answer: B. Endomysium
📅 NEET 2018

🔵 Q12. The functional and structural unit of muscle is
🟡 A. Myosin
🟡 B. Actin
🟡 C. Sarcomere
🟡 D. Troponin
🟢 Answer: C. Sarcomere
📅 AIPMT 2010

🔵 Q13. The structural protein of microtubules is
🟡 A. Tubulin
🟡 B. Actin
🟡 C. Myosin
🟡 D. Keratin
🟢 Answer: A. Tubulin
📅 NEET 2015

🔵 Q14. Which of the following is not a synovial joint?
🟡 A. Hinge
🟡 B. Pivot
🟡 C. Suture
🟡 D. Ball-and-socket
🟢 Answer: C. Suture
📅 AIPMT 2014

🔵 Q15. Muscle fatigue sets in due to accumulation of
🟡 A. Pyruvic acid
🟡 B. Lactic acid
🟡 C. Uric acid
🟡 D. Citric acid
🟢 Answer: B. Lactic acid
📅 NEET 2017

🔵 Q16. The outermost covering of a skeletal muscle is
🟡 A. Endomysium
🟡 B. Epimysium
🟡 C. Perimysium
🟡 D. Sarcolemma
🟢 Answer: B. Epimysium
📅 AIPMT 2012

🔵 Q17. The junction between two neurons is called
🟡 A. Node of Ranvier
🟡 B. Synapse
🟡 C. Neuromuscular junction
🟡 D. Axon hillock
🟢 Answer: B. Synapse
📅 NEET 2019

🔵 Q18. The Z line is located at the centre of
🟡 A. H-zone
🟡 B. A-band
🟡 C. I-band
🟡 D. Sarcomere
🟢 Answer: C. I-band
📅 AIPMT 2015

🔵 Q19. In a relaxed muscle fibre, the A-band contains
🟡 A. Actin only
🟡 B. Myosin only
🟡 C. Both actin and myosin
🟡 D. Z lines
🟢 Answer: C. Both actin and myosin
📅 NEET 2016

🔵 Q20. Red muscle fibres are rich in
🟡 A. Myoglobin and mitochondria
🟡 B. Glycogen only
🟡 C. Sarcolemma only
🟡 D. ATP only
🟢 Answer: A. Myoglobin and mitochondria
📅 AIPMT 2011

🔵 Q21. Ball-and-socket joint is an example of
🟡 A. Uniaxial joint
🟡 B. Biaxial joint
🟡 C. Multiaxial joint
🟡 D. Fixed joint
🟢 Answer: C. Multiaxial joint
📅 NEET 2015

🔵 Q22. The region of sarcomere that shortens during muscle contraction is
🟡 A. A-band
🟡 B. H-zone
🟡 C. M-line
🟡 D. Z-line
🟢 Answer: B. H-zone
📅 AIPMT 2013

🔵 Q23. Which type of joint is found between atlas and axis vertebrae?
🟡 A. Ball-and-socket
🟡 B. Hinge
🟡 C. Pivot
🟡 D. Gliding
🟢 Answer: C. Pivot
📅 NEET 2014

🔵 Q24. The type of movement in cilia and flagella is
🟡 A. Amoeboid
🟡 B. Gliding
🟡 C. Ciliary
🟡 D. Muscular
🟢 Answer: C. Ciliary
📅 AIPMT 2010

🔵 Q25. The role of Ca²⁺ in muscle contraction is to
🟡 A. Break ATP to release energy
🟡 B. Remove tropomyosin inhibition by binding to troponin
🟡 C. Bind to actin to form cross-bridges
🟡 D. Activate myosin ATPase directly
🟢 Answer: B. Remove tropomyosin inhibition by binding to troponin
📅 NEET 2017

🔵 Q26. Which joint is present between the carpals of the wrist?
🟡 A. Hinge joint
🟡 B. Pivot joint
🟡 C. Gliding joint
🟡 D. Ball-and-socket joint
🟢 Answer: C. Gliding joint
📅 AIPMT 2013

🔵 Q27. The protein that covers active sites on actin filaments during muscle relaxation is
🟡 A. Troponin
🟡 B. Tropomyosin
🟡 C. Myosin
🟡 D. Calmodulin
🟢 Answer: B. Tropomyosin
📅 NEET 2018

🔵 Q28. ATPase activity is found in
🟡 A. Actin head
🟡 B. Myosin head
🟡 C. Troponin complex
🟡 D. Tropomyosin
🟢 Answer: B. Myosin head
📅 AIPMT 2014

🔵 Q29. Myoglobin is abundant in
🟡 A. White fibres
🟡 B. Red fibres
🟡 C. Both red and white fibres equally
🟡 D. None of these
🟢 Answer: B. Red fibres
📅 NEET 2016

🔵 Q30. The sarcolemma is the
🟡 A. Plasma membrane of muscle fibre
🟡 B. Myosin filament
🟡 C. Actin filament
🟡 D. Z-line
🟢 Answer: A. Plasma membrane of muscle fibre
📅 AIPMT 2015

🔵 Q31. Osteocytes occur in
🟡 A. Cartilage
🟡 B. Bone
🟡 C. Ligament
🟡 D. Tendon
🟢 Answer: B. Bone
📅 NEET 2014

🔵 Q32. Chondrocytes occur in
🟡 A. Ligaments
🟡 B. Cartilage
🟡 C. Bone
🟡 D. Muscles
🟢 Answer: B. Cartilage
📅 AIPMT 2012

🔵 Q33. Ligaments connect
🟡 A. Muscle to bone
🟡 B. Bone to bone
🟡 C. Muscle to muscle
🟡 D. Cartilage to bone
🟢 Answer: B. Bone to bone
📅 NEET 2019

🔵 Q34. Tendons connect
🟡 A. Muscle to bone
🟡 B. Bone to bone
🟡 C. Muscle to muscle
🟡 D. Cartilage to bone
🟢 Answer: A. Muscle to bone
📅 AIPMT 2013

🔵 Q35. The functional unit of contraction in a skeletal muscle fibre is
🟡 A. Myofibril
🟡 B. Sarcomere
🟡 C. Cross bridge
🟡 D. Z-band
🟢 Answer: B. Sarcomere
📅 NEET 2017

🔵 Q36. The joint between femur and acetabulum is
🟡 A. Pivot joint
🟡 B. Ball-and-socket joint
🟡 C. Hinge joint
🟡 D. Saddle joint
🟢 Answer: B. Ball-and-socket joint
📅 AIPMT 2010

🔵 Q37. The contractile proteins actin and myosin form
🟡 A. Thin and thick filaments respectively
🟡 B. Thick and thin filaments respectively
🟡 C. Both thin filaments
🟡 D. Both thick filaments
🟢 Answer: A. Thin and thick filaments respectively
📅 NEET 2015

🔵 Q38. The junction between a motor neuron and a muscle fibre is
🟡 A. Synapse
🟡 B. Neuromuscular junction
🟡 C. Node of Ranvier
🟡 D. Axon terminal
🟢 Answer: B. Neuromuscular junction
📅 AIPMT 2014

🔵 Q39. The dark band of striated muscle fibre is known as
🟡 A. I-band
🟡 B. Z-band
🟡 C. A-band
🟡 D. H-zone
🟢 Answer: C. A-band
📅 NEET 2018

🔵 Q40. During muscle contraction, the I-band
🟡 A. Shortens
🟡 B. Remains unchanged
🟡 C. Disappears completely
🟡 D. Lengthens
🟢 Answer: A. Shortens
📅 AIPMT 2012

🔵 Q41. Which element activates muscle contraction?
🟡 A. Potassium
🟡 B. Calcium
🟡 C. Sodium
🟡 D. Magnesium
🟢 Answer: B. Calcium
📅 NEET 2016

🔵 Q42. In a relaxed muscle fibre, the binding sites for myosin are blocked by
🟡 A. Troponin
🟡 B. Tropomyosin
🟡 C. Calmodulin
🟡 D. ATPase
🟢 Answer: B. Tropomyosin
📅 AIPMT 2015

🔵 Q43. The type of joint found between vertebrae is
🟡 A. Hinge joint
🟡 B. Ball-and-socket joint
🟡 C. Gliding joint
🟡 D. Cartilaginous joint
🟢 Answer: D. Cartilaginous joint
📅 NEET 2017

🔵 Q44. The cross bridges are formed during contraction by
🟡 A. Actin heads binding to tropomyosin
🟡 B. Myosin heads binding to actin
🟡 C. Troponin binding to ATP
🟡 D. Tropomyosin binding to calcium
🟢 Answer: B. Myosin heads binding to actin
📅 AIPMT 2013

🔵 Q45. The skeletal muscles store oxygen in the form of
🟡 A. Hemoglobin
🟡 B. Myoglobin
🟡 C. Oxyhemocyanin
🟡 D. Tropomyosin
🟢 Answer: B. Myoglobin
📅 NEET 2014

🔵 Q46. The point where a muscle is attached to a moving bone is called its
🟡 A. Origin
🟡 B. Insertion
🟡 C. Fixator
🟡 D. Lever
🟢 Answer: B. Insertion
📅 AIPMT 2010

🔵 Q47. A sarcomere extends between two successive
🟡 A. A-bands
🟡 B. M-lines
🟡 C. Z-lines
🟡 D. H-zones
🟢 Answer: C. Z-lines
📅 NEET 2019

🔵 Q48. The connective tissue covering bundles of muscle fibres is
🟡 A. Epimysium
🟡 B. Perimysium
🟡 C. Endomysium
🟡 D. Sarcolemma
🟢 Answer: B. Perimysium
📅 AIPMT 2014

🔵 Q49. Which muscle fibre type is adapted for rapid contractions but fatigues quickly?
🟡 A. Red fibres
🟡 B. White fibres
🟡 C. Intermediate fibres
🟡 D. Cardiac fibres
🟢 Answer: B. White fibres
📅 NEET 2017

🔵 Q50. Calcium ions are stored in muscle fibre within the
🟡 A. Sarcolemma
🟡 B. Sarcoplasm
🟡 C. Sarcoplasmic reticulum
🟡 D. Myofibrils
🟢 Answer: C. Sarcoplasmic reticulum
📅 AIPMT 2015

PRACTICE SETS FROM THIS LESSON

🔵 Question 1:
The ability of an organism to move from one place to another is called:
🔴 1️⃣ Movement
🟢 2️⃣ Locomotion
🟡 3️⃣ Contraction
🔵 4️⃣ Relaxation
✔️ Answer: 2️⃣ Locomotion

🔵 Question 2:
Which of the following shows only movement but not locomotion?
🔴 1️⃣ Amoeba
🟢 2️⃣ Human hand movement
🟡 3️⃣ Paramecium
🔵 4️⃣ Earthworm
✔️ Answer: 2️⃣ Human hand movement

🔵 Question 3:
Cilia help in locomotion in:
🔴 1️⃣ Amoeba
🟢 2️⃣ Paramecium
🟡 3️⃣ Euglena
🔵 4️⃣ Earthworm
✔️ Answer: 2️⃣ Paramecium

🔵 Question 4:
Flagella help in locomotion in:
🔴 1️⃣ Amoeba
🟢 2️⃣ Euglena
🟡 3️⃣ Paramecium
🔵 4️⃣ Earthworm
✔️ Answer: 2️⃣ Euglena

🔵 Question 5:
Pseudopodia help in locomotion in:
🔴 1️⃣ Amoeba
🟢 2️⃣ Euglena
🟡 3️⃣ Paramecium
🔵 4️⃣ Hydra
✔️ Answer: 1️⃣ Amoeba

🔵 Question 6:
The structural and functional unit of muscle is:
🔴 1️⃣ Myofibril
🟢 2️⃣ Sarcomere
🟡 3️⃣ Muscle fibre
🔵 4️⃣ Actin
✔️ Answer: 2️⃣ Sarcomere

🔵 Question 7:
The contractile protein of muscle is:
🔴 1️⃣ Tubulin
🟢 2️⃣ Actin and Myosin
🟡 3️⃣ Elastin
🔵 4️⃣ Collagen
✔️ Answer: 2️⃣ Actin and Myosin

🔵 Question 8:
Which type of muscles are voluntary?
🔴 1️⃣ Skeletal
🟢 2️⃣ Smooth
🟡 3️⃣ Cardiac
🔵 4️⃣ Involuntary
✔️ Answer: 1️⃣ Skeletal

🔵 Question 9:
Which muscles are involuntary and non-striated?
🔴 1️⃣ Skeletal
🟢 2️⃣ Smooth
🟡 3️⃣ Cardiac
🔵 4️⃣ Voluntary
✔️ Answer: 2️⃣ Smooth

🔵 Question 10:
Which muscles are involuntary but striated?
🔴 1️⃣ Skeletal
🟢 2️⃣ Cardiac
🟡 3️⃣ Smooth
🔵 4️⃣ None
✔️ Answer: 2️⃣ Cardiac

🔵 Question 11:
The repeating unit between two Z-lines is called:
🔴 1️⃣ Myofibril
🟢 2️⃣ Sarcomere
🟡 3️⃣ Sarcolemma
🔵 4️⃣ Sarcoplasm
✔️ Answer: 2️⃣ Sarcomere

🔵 Question 12:
The region of a sarcomere containing only actin is:
🔴 1️⃣ A-band
🟢 2️⃣ I-band
🟡 3️⃣ H-zone
🔵 4️⃣ Z-line
✔️ Answer: 2️⃣ I-band

🔵 Question 13:
The region containing both actin and myosin is:
🔴 1️⃣ A-band
🟢 2️⃣ I-band
🟡 3️⃣ H-zone
🔵 4️⃣ Z-line
✔️ Answer: 1️⃣ A-band

🔵 Question 14:
The region containing only myosin is:
🔴 1️⃣ A-band
🟢 2️⃣ H-zone
🟡 3️⃣ I-band
🔵 4️⃣ Z-line
✔️ Answer: 2️⃣ H-zone

🔵 Question 15:
Which ion initiates muscle contraction?
🔴 1️⃣ Na⁺
🟢 2️⃣ Ca²⁺
🟡 3️⃣ K⁺
🔵 4️⃣ Mg²⁺
✔️ Answer: 2️⃣ Ca²⁺

🔵 Question 16:
During muscle contraction, which band remains unchanged?
🔴 1️⃣ A-band
🟢 2️⃣ I-band
🟡 3️⃣ H-zone
🔵 4️⃣ Sarcomere length
✔️ Answer: 1️⃣ A-band

🔵 Question 17:
Which of the following disappears during muscle contraction?
🔴 1️⃣ A-band
🟢 2️⃣ H-zone
🟡 3️⃣ I-band
🔵 4️⃣ Z-line
✔️ Answer: 2️⃣ H-zone

🔵 Question 18:
Which chemical supplies energy for muscle contraction?
🔴 1️⃣ NADH
🟢 2️⃣ ATP
🟡 3️⃣ GTP
🔵 4️⃣ FADH₂
✔️ Answer: 2️⃣ ATP

🔵 Question 19:
The enzyme that splits ATP during contraction is:
🔴 1️⃣ Myosin ATPase
🟢 2️⃣ Actinase
🟡 3️⃣ Peptidase
🔵 4️⃣ Lipase
✔️ Answer: 1️⃣ Myosin ATPase

🔵 Question 20:
Muscle fatigue occurs due to accumulation of:
🔴 1️⃣ Urea
🟢 2️⃣ Lactic acid
🟡 3️⃣ CO₂
🔵 4️⃣ Creatinine
✔️ Answer: 2️⃣ Lactic acid

🔵 Question 21:
Which connective tissue covers an entire muscle?
🔴 1️⃣ Perimysium
🟢 2️⃣ Epimysium
🟡 3️⃣ Endomysium
🔵 4️⃣ Sarcolemma
✔️ Answer: 2️⃣ Epimysium

🔵 Question 22:
Which connective tissue covers each muscle fibre?
🔴 1️⃣ Epimysium
🟢 2️⃣ Endomysium
🟡 3️⃣ Perimysium
🔵 4️⃣ Sarcolemma
✔️ Answer: 2️⃣ Endomysium

🔵 Question 23:
Which connective tissue surrounds a bundle of muscle fibres?
🔴 1️⃣ Epimysium
🟢 2️⃣ Perimysium
🟡 3️⃣ Endomysium
🔵 4️⃣ Sarcolemma
✔️ Answer: 2️⃣ Perimysium

🔵 Question 24:
The contractile protein actin is a:
🔴 1️⃣ Thick filament
🟢 2️⃣ Thin filament
🟡 3️⃣ Elastic filament
🔵 4️⃣ Intermediate filament
✔️ Answer: 2️⃣ Thin filament

🔵 Question 25:
The contractile protein myosin is a:
🔴 1️⃣ Thin filament
🟢 2️⃣ Thick filament
🟡 3️⃣ Elastic filament
🔵 4️⃣ Intermediate filament
✔️ Answer: 2️⃣ Thick filament

🔵 Question 26:
The functional unit of skeletal muscle is:
🔴 1️⃣ Myofibril
🟢 2️⃣ Sarcomere
🟡 3️⃣ Myofilament
🔵 4️⃣ Z-line
✔️ Answer: 2️⃣ Sarcomere

🔵 Question 27:
The neurotransmitter at neuromuscular junction is:
🔴 1️⃣ Dopamine
🟢 2️⃣ Acetylcholine
🟡 3️⃣ Adrenaline
🔵 4️⃣ Noradrenaline
✔️ Answer: 2️⃣ Acetylcholine

🔵 Question 28:
Which part of the brain controls voluntary movement?
🔴 1️⃣ Cerebrum
🟢 2️⃣ Cerebellum
🟡 3️⃣ Medulla
🔵 4️⃣ Pons
✔️ Answer: 1️⃣ Cerebrum

🔵 Question 29:
Which part of the brain maintains body balance?
🔴 1️⃣ Cerebrum
🟢 2️⃣ Cerebellum
🟡 3️⃣ Medulla
🔵 4️⃣ Pons
✔️ Answer: 2️⃣ Cerebellum

🔵 Question 30:
Calcium is stored in muscles in:
🔴 1️⃣ Sarcolemma
🟢 2️⃣ Sarcoplasmic reticulum
🟡 3️⃣ Sarcoplasm
🔵 4️⃣ Sarcomere
✔️ Answer: 2️⃣ Sarcoplasmic reticulum

🔵 Question 31:
Which band shortens during muscle contraction?
🔴 1️⃣ A-band
🟢 2️⃣ I-band
🟡 3️⃣ H-zone
🔵 4️⃣ Both 2 and 3
✔️ Answer: 4️⃣ Both 2 and 3

🔵 Question 32:
The cross-bridges are formed by:
🔴 1️⃣ Actin
🟢 2️⃣ Myosin heads
🟡 3️⃣ Tropomyosin
🔵 4️⃣ Troponin
✔️ Answer: 2️⃣ Myosin heads

🔵 Question 33:
Which protein covers the active sites on actin filament?
🔴 1️⃣ Troponin
🟢 2️⃣ Tropomyosin
🟡 3️⃣ Myosin
🔵 4️⃣ ATPase
✔️ Answer: 2️⃣ Tropomyosin

🔵 Question 34:
The sliding filament theory was proposed by:
🔴 1️⃣ Huxley and Niedergerke
🟢 2️⃣ Darwin
🟡 3️⃣ Schleiden
🔵 4️⃣ Schwann
✔️ Answer: 1️⃣ Huxley and Niedergerke

🔵 Question 35:
The total number of bones in human skeleton is:
🔴 1️⃣ 200
🟢 2️⃣ 206
🟡 3️⃣ 210
🔵 4️⃣ 208
✔️ Answer: 2️⃣ 206

🔵 Question 36:
The human skull consists of:
🔴 1️⃣ 10 bones
🟢 2️⃣ 22 bones
🟡 3️⃣ 24 bones
🔵 4️⃣ 26 bones
✔️ Answer: 2️⃣ 22 bones

🔵 Question 37:
Number of vertebrae in vertebral column is:
🔴 1️⃣ 30
🟢 2️⃣ 33
🟡 3️⃣ 36
🔵 4️⃣ 40
✔️ Answer: 2️⃣ 33

🔵 Question 38:
Number of cervical vertebrae is:
🔴 1️⃣ 7
🟢 2️⃣ 12
🟡 3️⃣ 5
🔵 4️⃣ 8
✔️ Answer: 1️⃣ 7

🔵 Question 39:
Number of thoracic vertebrae is:
🔴 1️⃣ 7
🟢 2️⃣ 12
🟡 3️⃣ 5
🔵 4️⃣ 8
✔️ Answer: 2️⃣ 12

🔵 Question 40:
Number of lumbar vertebrae is:
🔴 1️⃣ 5
🟢 2️⃣ 7
🟡 3️⃣ 8
🔵 4️⃣ 12
✔️ Answer: 1️⃣ 5

🔵 Question 41:
The smallest bone in human body is:
🔴 1️⃣ Stapes
🟢 2️⃣ Incus
🟡 3️⃣ Malleus
🔵 4️⃣ Hyoid
✔️ Answer: 1️⃣ Stapes

🔵 Question 42:
The largest bone in human body is:
🔴 1️⃣ Tibia
🟢 2️⃣ Femur
🟡 3️⃣ Humerus
🔵 4️⃣ Fibula
✔️ Answer: 2️⃣ Femur

🔵 Question 43:
The total number of ribs in human body is:
🔴 1️⃣ 10 pairs
🟢 2️⃣ 12 pairs
🟡 3️⃣ 14 pairs
🔵 4️⃣ 16 pairs
✔️ Answer: 2️⃣ 12 pairs

🔵 Question 44:
The ribcage protects:
🔴 1️⃣ Brain
🟢 2️⃣ Heart and lungs
🟡 3️⃣ Stomach
🔵 4️⃣ Kidneys
✔️ Answer: 2️⃣ Heart and lungs

🔵 Question 45:
Atlas is the:
🔴 1️⃣ First cervical vertebra
🟢 2️⃣ Second cervical vertebra
🟡 3️⃣ Third cervical vertebra
🔵 4️⃣ First thoracic vertebra
✔️ Answer: 1️⃣ First cervical vertebra

🔵 Question 46:
Axis is the:
🔴 1️⃣ First cervical vertebra
🟢 2️⃣ Second cervical vertebra
🟡 3️⃣ Third cervical vertebra
🔵 4️⃣ Last lumbar vertebra
✔️ Answer: 2️⃣ Second cervical vertebra

🔵 Question 47:
The joint between atlas and axis is:
🔴 1️⃣ Hinge
🟢 2️⃣ Pivot
🟡 3️⃣ Ball and socket
🔵 4️⃣ Saddle
✔️ Answer: 2️⃣ Pivot

🔵 Question 48:
The joint between humerus and pectoral girdle is:
🔴 1️⃣ Ball and socket
🟢 2️⃣ Hinge
🟡 3️⃣ Pivot
🔵 4️⃣ Saddle
✔️ Answer: 1️⃣ Ball and socket

🔵 Question 49:
The joint between phalanges is:
🔴 1️⃣ Pivot
🟢 2️⃣ Hinge
🟡 3️⃣ Saddle
🔵 4️⃣ Ball and socket
✔️ Answer: 2️⃣ Hinge

🔵 Question 50:
The bone of upper arm is:
🔴 1️⃣ Radius
🟢 2️⃣ Ulna
🟡 3️⃣ Humerus
🔵 4️⃣ Femur
✔️ Answer: 3️⃣ Humerus

Important Notice : The lessons and study materials up to July–August 2025 have been sent. Soon, after receiving feedback from teachers and students, we will deliver the latest and more innovative study materials for the upcoming months.