The Skeletal System

Functions of the Skeletal System, Types of Skeleton in Animals, Structure of a Long Bone, and The Human Skeletal System

What is a skeleton?

Hardened body portion

What is the skeletal system?

Framework of the body

What are the functions of the skeletal system?

Physical Support, Protection, Muscle attachment, Mineral Storage, and RBC manufacture

Which minerals are stored by bones?

Calcium and phosphorus

What does the skeletal system provide for locomotion?

Muscle attachment and leverage

Where are red blood cells manufactured in long bones?

Bone marrow

What type of skeleton is found outside the body?

Exoskeleton

What type of skeleton is found inside the body?

Endoskeleton

Which are examples of exoskeletons?

Crustacean shells, Insect skeletons, Turtle carapace, and Turtle plastron

What type of skeleton consists of hardened, rigid, segmented, cellular bones?

Endoskeleton

Which two materials are examples of an endoskeleton?

Cartilage and bone

What is the fluid core of a hydrostatic skeleton made of?

Water or body fluid

What tough membrane surrounds and protects a bone?

Periosteum

What does the periosteum produce for bone growth?

Bone-forming cells

What is the dense material beneath the periosteum?

Compact bone

What is the main strength function of compact bone?

Carrying heavy objects

Where is spongy bone located according to the material?

At the bone end

What effect does spongy bone have on a bone knob?

Makes it light

What structures are abundant in marrow?

Nerves and blood vessels

Where is red marrow found?

Flat bones

What is the function of red marrow?

Produces RBCs

What is Ossification?

Cartilage-to-bone transformation

What compounds are deposited during ossification?

Calcium compounds

What is the result of calcium deposition during ossification?

Increased bone strength

What type of bone develops immediately into hard bone?

Membrane bone

Which division includes the skull, hyoid, sternum, ribs, and vertebral column?

Axial skeleton

Which division includes the pectoral girdle and limbs?

Appendicular skeleton

Structures belong to the axial skeleton?

Skull, Hyoid, Sternum, Ribs, and Vertebral column

Structures belong to the appendicular skeleton?

Pectoral girdle, Pelvic girdle, Upper limbs, and Lower limbs

What is the main structural focus of the axial skeleton?

Body axis and support

Axial skeleton

Skull, ribs, vertebral column, Hyoid, Sternum

What is the skull?

Bony framework of head

What does the skull protect?

Brain and sense organs

Structure of a long bone

Periosteum, Compact bone, Marrow, and Spongy bone

Periosteum

Tough membrane that surrounds & protects bone

Holds muscles in place & produces bone-forming cells responsible for bone growth

Periosteum

Compact bone

Dense mat’l beneath the periosteum

Gives bones strength to carry heavy objects

Compact bone

Makes the bone knob light

Spongy bone

At the end of bone knob

Spongy bone

Marrow

Soft inner part of bone

Rich with nerves & blood vessels

Marrow

Types of Marrow

Red marrow and Yellow marrow

Red marrow

Found on flat bones (eg. Ribs, sternum)

Yellow marrow

Found on central cavity of long bones

Made up of fat cells and serves as storage depot for fats

Yellow marrow

Ossification

The process where cartilage are transformed into bones

Cartilage-to-bone transformation

Ossification

Involves deposition of calcium compounds between bone cells resulting in increased strength of bones

Ossification

Types of bones according to formation

Cartilage Bone and Membrane Bone

starts first as a cartilage (chondrification) and later hardens into a

bone (ossification)

Cartilage Bone

Develops immediately into a hard bone

Membrane Bone

Two divisions of the Human Skeleton

Axial Skeleton and Appendicular Skeleton

Consists of Skull Hyoid, Sternum, Ribs, and Vertebral column

Axial Skeleton

Consists of Pectoral girdle, Pelvic girdle, Upper limbs, and Lower limbs

Appendicular Skeleton

means "in front of" or "toward the front surface" of the body or an organ

Anterior

Posterior

to the back side of the body or rear of the body

Axial Skeleton consists of

Skull, Hyoid, Sternum, Ribs, Vertebral column

Bony framework of the head

Skull

Encloses & protects the brain & sense organs

Skull

Consists of

Cranial bones and Facial bones

How many are the Cranial bones

8

Facial bones

14

Bones are joined together by immovable joint called suture

Skull

Suture

Immovable joint that joins most skull bones

Mandible

Skull bone that’s an exception to the immovable sutures

Where is the hyoid located?

Upper anterior neck

Small isolated bone located in the upper anterior part of the neck

Hyoid

Supports the tongue and larynx (voice box)

Hyoid

Flat dagger-shaped bone in the middle of the chest

Sternum

For attachment of ribs that together form the rib cage which protects internal organs (heart, lungs)

Sternum

Sternum is composed of:

Manubrium, Body, and Xiphoid process

Upper part of the sternum

Manubrium

Elongated middle segment of the sternum

Body

Small terminal piece of the sternum

Xiphoid process

Flat bones attached to the sternum

Ribs

Protect organs in the thoracic cavity (heart, lungs) and Supports the chest wall

Ribs

What is the line on the left pointing to?

Sternum

What is the line on the right pointing to?

Rib Cage

What is the pink line pointing to?

Hyoid Bone

What is the purple line pointing to?

Larynx (Voice box)

What’s in the heart bracket?

Cervical Curve

What’s in the star bracket?

Thoracic curve

What’s in the fire bracket?

Lumbar Curve

What’s in the eye bracket?

Sacral Curve

What’s the green line pointing to?

Cervical vertebrae

What’s the red line pointing to?

Thoracic vertebrae

What’s the blue line pointing to?

Lumbar vertebrae

What’s the pink line pointing to?

Sacrum

What’s the purple line pointing to?

Coccygeal vertebrae

Axial support of the body also called the spinal column or backbone

Vertebral column

Composed of 33 irregularly shaped bones called vertebrae

Vertebral column

Common features of Vertebral column: body & neural arch

24 vertebrae

What are two other names for the vertebral column?

Spinal Column and Backbone

How many fused bones form the coccyx (coccygeal vertebrae)?

4

How many thoracic vertebrae are there?

12

How many lumbar vertebrae are there?

5

How many fused bones form the sacrum (sacral vertebrae)?

5

What’s the red line pointing to?

Scapula