A&P SEMESTER REVIEW

What are the main functions of the skeletal system?

Support, protection, movement, mineral storage (calcium & phosphorus), and blood cell production (hematopoiesis).

How many bones are in an adult human body?

206

Which bones are in the axial skeleton?

Skull, vertebral column, rib cage, sternum.

Which bones are in the appendicular skeleton?

Limbs, pectoral girdle, pelvic girdle.

Where is the tibia located?

Shin bone in the lower leg.

Where is the patella located?

Kneecap

Where is the femur located?

Thigh bone.

Where are the ulna and radius located?

Forearm (ulna = medial, radius = lateral).

Where is the xiphoid process?

Inferior tip of the sternum.

Where is the manubrium?

Superior portion of the sternum.

What are the main parts of a long bone?

Shaft (diaphysis), ends (epiphysis), compact bone, spongy bone, articular cartilage, medullary cavity, central canal.

What are carpals?

wrist bones

What are metacarpals?

hand bones

What are the types of bones by shape?

Long (femur), short (carpals), flat (sternum, scapula), irregular (vertebrae).

Function of red bone marrow?

Produces red blood cells

Function of yellow bone marrow?

stores fat

Osteoblasts

build bone

Osteoclasts

break down bone

Osteocytes

maintains bone

What is the epiphyseal plate?

Growth plate where bone lengthens

What is articular cartilage?

Smooth tissue covering bone ends at joints to reduce friction.

What is the most abundant mineral in the body?

Calcium

What cartilage forms the embryonic skeleton?

Hyaline cartilage.

What is synovial fluid?

Lubricant in synovial joints.

What is a fossa?

A depression or hollow in bone.

What is the periosteum?

Outer fibrous covering of bone

What is bone matrix made of?

Collagen fibers and mineral salts (calcium phosphate).

Sutures

immovable skull joints

Fontanelles

soft spots in infant skull,

Lacunae

small spaces housing osteocytes

Fractures

broken bones

Open fractures

one pierces skin,

Closed fractures

no skin break

Spiral Fractures

Twisted fractures

Comminuted Fractures

bone shatters into pieces.

What is a depressed fracture?

Bone pressed inward, common in children due to flexible matrix.

What tissue type is osseous tissue?

Connective tissue.

What is ossification?

Process of bone formation

True ribs

True = directly attached to sternum (1–7),

False Ribs

indirectly attached (8–10)

Floating Ribs

no anterior attachment (11–12)

What are the four stages of bone healing?

Hematoma formation → Fibrocartilaginous callus → Bony callus → Bone remodeling.

What is the primary ossification center?

Region in diaphysis where bone development begins during endochondral ossification.

First Step of endochondral ossification

Cartilage enlarges; Chondrocytes die

Second Step of endochondral ossification

blood vessels grow into perichondrium; cells convert to osteoblasts; shaft becomes covered with superficial bone

3rd Step of endochondral ossification

more blood supply and osteoblasts; produces spongy bone; formation spreads on shaft

4th step of endochondral ossification

Osteoclasts create medullary cavity; appositional growth

5th step of endochondral ossification

epiphysis centers calcify; blood and osteoblasts move in; secondary ossification centers

6th step of endochondral ossification

Epiphysis filled with spongy bone; cartilage remains at joints; epiphyseal plate in metaphysis

What are the primary functions of the muscular system?

Movement of the body, maintenance of posture, stabilization of joints, and heat production through muscle activity.

How are muscles named?

Location, Shape, Size, Directions of fibers, # of origins, Actions

What are the behavioral (functional) characteristics of muscle tissue?

1. Excitability (Irritability): Ability to respond to a stimulus (usually a nerve impulse).

2. Contractility: Ability to shorten and generate force.

3. Extensibility: Ability to be stretched beyond resting length.

4. Elasticity: Ability to return to original shape after stretching or contracting.

Arm Anterior Muscles

Biceps brachii, brachialis

Arm Posterior Muscles

Triceps brachii

ULTIMATE STUDY GUIDE: MUSCULAR, ENDOCRINE

& INTEGUMENTARY SYSTEMS

Muscular System – Key Facts

• Behavioral characteristics: excitability, contractility, extensibility, elasticity

• Agonist = prime mover; Antagonist = opposes movement

• Contractile unit: sarcomere

• Skeletal muscle count: ~650

• Origin = fixed attachment; Insertion = movable attachment

• Axial muscles = head, neck, trunk; Appendicular = limbs

Muscle Structure (Small → Large)

• Myofilaments (actin & myosin)

• Sarcomere

• Myofibril

• Muscle fiber

• Fascicle

• Whole muscle

Connective Tissue Layers

• Endomysium – surrounds muscle fiber

• Perimysium – surrounds fascicle

• Epimysium – surrounds whole muscle

Muscle Fiber Arrangements

• Parallel – fibers run parallel

• Pennate – feather-like

• Convergent – broad origin, narrow insertion

• Circular (sphincter) – surrounds opening

Muscle Movements

• Flexion – decreases joint angle

• Extension – increases joint angle

• Adduction – toward midline

• Abduction – away from midline

• Supination – palm up

• Pronation – palm down

• Dorsiflexion – foot up

• Plantar flexion – foot down

• Opposition – thumb to fingers

• Circumduction – circular motion

• Rotation – turning on axis

Sarcomere & Contraction

• Actin = thin filament

• Myosin = thick filament

• Tropomyosin blocks binding sites

• Troponin binds calcium

• Calcium allows myosin to bind actin

• ATP provides energy for contraction & relaxation

• Rigor mortis caused by lack of ATP