A&P Exam 2

What are the different types of bones?

Long bones, Flat bones, Short bones, Irregular shaped bones

Examples of irregular bones:

Vertebrae, Pelvis, Sacrum, Coccyx, Mandible, Sphenoid, Ethmoid, Hyoid

Irregular shaped bones?

Have their own shape that doesn’t fit other bone types

Examples of short bones:

Carpals, Tarsals

Short bones are?

Cube-like in shape

Flat bones are?

Thinner bones

Examples of flat bones:

Bones that make up our skull, sternum, shoulder blades, ribs

Long bones are?

Longer than they are wide, typically cylindrical in shape with medullary cavity

Examples of long bones:

Humerus, Radius, Ulna, Metacarpals, metatarsals, Phalanges, Femur, Tibia, Fibula, clavicle

What are the different types of bone cells?

Osteogenic, Osteoblast, Osteocyte, Osteoclast

Stem-cell

a cell capable of change, hasn’t decided what its gonna be yet

Osteogenic cell

Stem-cell capable of cell division, capable of becoming osteoblasts or osteoclasts

Osteoblast cell

Makes new bone tissue by secreting a gel with lots of collagen fibers

How does osteoblast work?

Inserts calcium phosphate crystals in between collagen fibers

Function of Collagen fibers in Osteoblast

Give bone its strength by allowing bone tissue to calcify and ossify

Osteocyte

Mature bone cell with little extensions that project through calcified bone tissue

Purpose of Osteocyte extensions

To maintain and monitor the stresses the surrounding bone tissue is experiencing

Osteoclast

Cell that breaks down bone

Bone remodeling

Process of constantly remaking bone

What is on the outer shell of a flat bone?

Compact bone

What is compact bone?

Dense bone tissue made of osteocytes

What is inside a flat bone?

Spongy bone

What is the Trabeculae of spongy bone?

Bone marrow, yellow and red

Yellow bone marrow

Adipose tissue

Red bone marrow

Tissue that is involved in the production of blood cells

Periosteum

Double layer of connective tissue that coats all bones

The outer layer of Periosteum is made of?

Dense irregular connective tissue, fibrous layer

The inner layer of Periosteum is made of?

Osteogenic cells, blood vessels

Endosteum

Layer of connective tissue that covers the walls of Trabeculae and medullary cavity

What are the ends of a long bone?

Epiphysis

What is the shaft of a long bone called?

Diaphysis

Medullary cavity

central empty cavity that contains marrow and is covered by endosteum

How do osteocytes get their nutrition?

From blood vessels that are in the bone

What is between epiphysis and diaphysis?

The epiphyseal plate

What is the epiphyseal plate?

A region of cartilage in children where growth happens, only in long bones

What happens in the epiphyseal plate?

Cartilage cells rapidly divide, calcify and die

How do flat bones grow?

Through ossification

How do bones develop?

Endochondral ossification and Intramembranous ossification

In which bones does endochondral ossification happen?

In long bones

Steps of endochondral ossification

A template of hyaline cartilage forms in the fetus, looks like smaller versions of the bone, forms a model of what bone will be

In which bones does Intramembranous ossification happen?

Flat bones

Intramembranous ossification

A slow process where a group of osteoblasts that start secreting bone tissue, collagen, calcium phosphate and spread out until flat bone is formed

What are different ways that bones break?

Greenstick, Spiral, Comminuted, Depression, Growth plate, compound

Greenstick fracture

Partial break, not all the way through the bone, common in children

Spiral fracture

When a bone experiences twisting forces that cause bone to break, common in athletes

Comminuted fracture

Bone breaks in two or more pieces, common in elderly

Depression fracture

crater-like dip forms, common in flat bones of skull

Growth plate fracture

Bone breaks on epiphyseal plate in growing kids

Compound fracture

bone breaks and pierces through the skin, dangerous because bacteria and infections can enter the body

What happens when a bone breaks?

A hematoma forms

How do bones heal after a fracture?

Blood vessels carrying macrophages start to invade where hematoma is to clean up broken pieces of bone, soft callus forms, new osteoblasts start making spongy bone until hard callus forms, finally bone remodeling

Soft callus

fibroblasts and chondroblasts start secreting collagen fibers and cartilage

How does the body control the amount of calcium in the blood?

a negative feedback loop that triggers PTH to stimulate vitamin D and osteoclasts

How does the parathyroid hormone work with calcium?

Tells kidney tubules to reabsorb calcium from urine, stimulates production of vitamin D to absorb calcium from food, stimulates osteoclasts to release calcium from bones

What is cartilage?

Important supportive connective tissue, made of cartilage cells located in capsules called lacunae, does not have blood supply, cannot heal well

What are the different types of cartilage, and where are they located?

Hyaline, Fibrocartilage, Elastic

Hyaline cartilage

Coats articulate surfaces of bones, prevents abrasion and friction as bones move past each other

Where is Hyaline cartilage found?

Found on tops of long bones, connects our ribs to sternum, trachea, nose

What is hyaline cartilage made of?

Cells called chondrocytes

What are chondrocytes?

A special type of fibroblasts that secrete collagen fibers, water, or elastic fibers

Fibrocartilage

Pillow that provides cushion between bones

Where is fibrocartilage found?

Intervertebral discs of the skeleton, pubic symphysis, meniscus of the knee

What is fibrocartilage made of?

Chondrocytes that secrete collagen fibers in a parallel arrangement

Elastic cartilage

Stretchy cartilage, not very common

What is elastic cartilage made of?

Chondrocytes that secrete elastic fibers

Where is elastic cartilage found?

External ear, epiglottis

What is a joint?

A union between two bones

What is a synovial joint?

A joint where there is movement that occurs between connecting bones

What are the different parts of a synovial joint?

Joint capsule, Hyaline cartilage, Synovial membrane/fluid, Ligaments

Joint capsule

Fibrous layer that encases the joint and functions as support

Synovial membrane

Inside joint capsule, secretes synovial fluid

What is synovial fluid?

An oil-like substance that lubricates and prevents friction and abrasion in the joint cavity

Cavitation

Air bubbles in synovial cavity fluid, makes a pop (like when you crack knuckles)

Ligaments

Help stabilize the entire joint

Bursae

Little ball of synovial fluid typically outside of synovial cavity to help prevent abrasions from bones, tendons, and muscles

Tendon sheath

Pancake of synovial membrane that wraps around an entire tendon

What are the six different types of synovial joints, and what are examples of each?

Condylar, Pivot, Plane, Hinge, Saddle, Ball and Socket

Condylar joint

Bones can move in any direction but cannot spin

Examples of Condylar joints

Metacarpal phalangeal joints, carpal joints, joint between most superior vertebrae and skull

Pivot joints

Allows bones to spin

Examples of Pivot joints

Joint that connects radius to ulnae, between first and second vertebrae

Plane Joint

Allows short bones to slide past each other

Examples of Plane joints

between short bones of carpals, tarsal bones, and between each vertebrae

Hinge Joint

Bones can only move in one axis

Examples of Hinge joint

Elbow, interphalangeal joints, joint that connects callus to distal ends of tibia and fibula

Saddle joint

Two axis of motion

Examples of Saddle joint

Where first metacarpal of thum connects to hallux

Ball and Socket Joint

Most flexible, allows bones to move in any direction and also spin

Examples of Ball and Socket Joint

Shoulder joints, Hip joints

Flexion

Angle between two bones decreases

Extension

Angle between two bones increases

Adduction

Limb is brought towards the body

Abduction

Limb is brought away from the body

Supination

When palm is facing forward, or elbows are flexed, bones are parallel

Pronation

When palm is facing down, or elbow is not flexed, bones are now crossed

toes are pointed up

Plantar flexion

toes are pointed down

Inversion

sole of the foot points inwards

Eversion

sole of the foot points outwards

What are the two cruciate ligaments? (deep internal)

Anterior Cruciate Ligament (ACL) and Posterior Cruciate Ligament (PCL)