Anatomy Test 2

5 primary functions of skeletal system

1. Support

2. Storage of minerals and lipids

3. Blood cell production

4. Protection

5. leverage

Long bone

Longer than it is wide; example: humerus

short bone

Roughly cube-shaped; example: carpal

Flat bone

Thin, flattened bone; example: parietal bone

Irregular bone

Complex shape; example: vertebra

Sesamoid bone

Bone that develops within a tendon; example: patella

Sutural bone

Small bone located within a skull suture

fossa

bowl/depression. Example: intercondyle fossa on femur

Tubercle

Small knob or protrusion exaple greater and lesser tubercle on humerus. none on femur

Tuberosity

Rough area. Each bone has only one. Example ulna tuberosity, deltoid tuberosity(humerus), radial tuberosity, ischial tuberosity, gluteal (femur), tibial tuberosity (front)

Condyle

Rounded end that articulates with another bone, usually distal. Example: Femur has medial/lateral epicondyle and condyle. Humerous is has medial/lateral epicondyle and condyle in middle with capitiium and trochea.

Sinus

cavity within bone to reduce bone density and weight

Diaphysis vs Metaphysis vs Epiphysis

Diaphysis → Shaft of a long bone

Epiphysis → End of a long bone

Metaphysis → Region between the diaphysis and epiphysis

Osteon

Basic

structural unit of compact bone

Importance of canaliculi

Allow osteocytes embedded in hard matrix to exchange nutrients/wastes and communicate through their extensions

Two major components of bone matrix

Mineral crystals (2/3) + protein fibers (1/3)

whats in mineral crystas of bone matrix and what does it do

Hydroxyapatite → Mineral crystals that contribute hardness/strength to bone

whats in protein fiber of matrix and what does it do

Collagen → Protein fibers that provide flexibility/tensile strength

spongey bone structure

Trabeculae (not osteons) with no blood vessals

spongey bone structure function

Reducses bone mass making bones light weight, space for bone marrow and distributes forces

yellow vs red bone marrow

Red bone marrow → Contains blood vessels; associated with blood cell production

Yellow bone marrow → Found in some bones and stores lipids

Periosteum. What is it and what are the functions

Covers and lines the inside of bones (outer membrane)

• Isolates bone

• Route for circulation and innervation

• Aids bone growth and repair

Endosteum. What is it and what are the functions

Inner membrane in central canal

• Lines medullary cavity

• Covers trabeculae

• Lines central canals

• Contains bone cells

• Active in growth and repair

Endochdonral Osstification

Bone builds from cartilage. Babies are mostly cartilage; then blood vessels develop nearby, which hollow out the cartilage to form bone. Hyaline cartilage remains at the ends of bones. Can be primary (diaphysis) and secondary (epiphysis)

Intramembranous ossification

Dermal bones such as mandible and clavicle.

Appositional Growth

Compact bone thickens and strengthens long bones with layers of circumferential lamellae. Bones dont get longer they get thicker

Bone remodeling

Ongoing replacement/recycling of bone matrix involving many bone cells which requires a blood supply

Why is remodeling important?

Daily maintenance, mineral recycling, adaptation to stress and fracture repair

Name 4 bone-cell types (make up 2% of bone mass, 98% matrix)

Osteogenic cells, osteoblasts, osteocytes, osteoclasts

Osteoprogenitor/Osteogenic cell

can transform into osteoblast or osteoclast, stem cell

Osteoblast

Bulids bone

Osteoclast

Destorys/ Reabsorbs bone. Breaks matrix down to maintain bone mass

Osteocyte

Mature bone cell that maintains bone matrix

Bone homeostasis

Balance between osteoblast bone building and osteoclast bone resorption

How do osteoclasts breakdown bone

Protease breaks down proteins. Cathepsin breaks down collagen. Low pH makes it acidic, which breaks down hydroxyapatite

explain chemical aspect of osteoclasts

inside osteroclast carbonic anahydrase enzyme speeds up process to make carbonic acid.

Why is calcium homeostasis so important

• bone strength

• muscle contracton

• nerve signaling

• blood clotting

• heart function

• 2nd messanger

• horomone realese

• heart function

Factors that effect bone remodeling

Lifting weights, diet, movement level, racket sports (using one arm more)

Calcitriol (thyroid gland)

hormone made in the kidneys

• helps absorb calcium and phosphorous from the digestive tract

• its synthesis requires Vitamin D3

Goal is to lower blood calcium levels

Bone → osteoclasts inhibited while osteoblasts continue locking calcium into matrix
Intestine → decreased calcium absorption
Kidney → allows more calcium loss

Parathyroid hormone

Goal is to raise blood calcium levels

Bone → increased calcium release
Intestine → increased calcium absorption
Kidney → retains more calcium → less lost in urine

What is the axial skeleton

forms the central axis of your body. It has the skull throacic cage and vertebrae

axial skeleton functions

• Supports and protects organs in body cavities

• Attaches muscles of the head, neck, and trunk

• Facilitates respiratory movements

• Stabilizes parts of the appendicular skeleton

Coronal suture

Frontal + parietal bones

Sagittal suture

Right parietal + left parietal

Lambdoid suture

Parietal bones + occipital bone

Squamous suture

Parietal + temporal

Metopic/frontal suture

Associated with the frontal bone; your lecture labels the frontal/metopic suture.

Sinuses. what are they lined with?

cavities that decrease the weight of the skull. Lined with mucous membranes to protect the entrances of the respiratory system, cleans air.

Functions of the temporal bones

• form lateral walls of cranium

• contribute to the zygomatic arches

• articulate with the mandible

• surround/protect the inner ear

• provide muscle attachment

Bony nasal septum

Perpendicular plate of ethmoid + vomer

jaw articulation

Temporal bone + mandible

zygomatic arch

Temporal process of zygomatic bone + zygomatic process of temporal bone

Functions of the sphenoid:

1. Forms part of the floor of the cranium

2. Unites the cranial and facial bones

3. Strengthen sides of the skull

4. Contains sphenoidal sinuse

• Functions of the ethmoid:

1. Forms anteromedial floor of cranium

2. Forms roof of the nasal cavity

3. Forms part of the nasal septum and medial orbital wall

4. Contains ethmoid air cells (small sinuses)

Nasal conchae function

The conchae increase the surface area/contact of air moving through the nasal cavity and create turbulence, helping condition inhaled air. Conchae help prepare incoming air before it travels deeper into the respiratory tract.

Vertebral arch

Pedicles + laminae

Hyoid bone

does NOT articulate with the skeleton.

Instead, it is held in place by muscles.

Its functions in your lecture include:

• supporting the larynx

• attaching muscles of the tongue

Vertebral column parts

Cervical → 7

Thoracic → 12

Lumbar → 5

Sacrum

Coccyx

what are c1 and c2 and their special features

atlas: occipital condyle

axis: dens

Cervical Vertebrae features

large foremen (thick spinal cord) , transverse foramen

Thoracic vertebrae features

Costal facets for rib connection, heart shaped body

Lumbar vertebrae

small foramen and big body

Rib classification

True ribs

Ribs 1–7

False ribs

Ribs 8–12

Floating ribs

Ribs 11–12

Important relationship:

All floating ribs are false ribs, but not all false ribs are floating ribs.

Rib articulations

Ribs articulate with thoracic vertebrae. Anteriorly, they articulatewitho the sternum through costal cartilage,

What is the appendicular skeleton

Think limbs + the structures attaching the limbs to the axial skeleton.

Pectoral Girdle and functions

Clavicle + scapula

functions:

1. Connects the arms to the body

2. Positions the shoulders

3. Provides a base for arm movement

4. Connects with the axial skeleton at the manubrium Bone Tissue (Chapter 6)

clavicle ends and Articulations

Sternal end (medial) → manubrium of sternum

Acromial end (lateral) → acromion of scapula

is radius or ulna lateral? do they articulate w eachother

Radius = lateral/thumb side

Ulna = medial/pinky side

Radius and ulna articulate with each other proximally AND distally.

Pelvic girdle and function

2 coxal bones

Each coxal bone is actually made from 3 fused bones:

Ilium + ischium + pubis

The pelvic girdle is strong enough to bear the weight of the body.

Pelvis

2 coxal bones + sacrum + coccyx

Patella

kneecap sesamoid bone (bone devloping in tendon)

Two important tarsal bones

Talus → involved in ankle articulation

Calcaneus → heel bone

Variations in the Skeleton (tells ppl abt how they lived)

• muscle strength and mass

• medical history

• sex and age

• body size

• nutrition/environment

• cause of death

types joints (3)

synarthrosis (immovable), amphiarthrosis (slightly movable), diarthrosis (freely movable)

suture

synarthrosis, coronal, saggital

gamphosis

synarthrosis tooth-maxillia/mandible

synchondrosis

synarthrosis, costal cartillage, epiphyseal cartillage/plates

synostosis

synarthrosis, metopic suture, ephiphyseal lines, coxal bone, transverse lines

syndesmosis

amphiarthrosis, interosseous membrane and distal tibia-fibula joint

synphysis

amphiarthrosis: pubic symphysis and intervertbreal discs

Gliding

Diarthrosis: intercarpal/intertarsal TMJ

Hinge

Diarthrosis: elblow, knee, ankle

Pivot

Diarthrosis: atlas-axis and radio-ulnar (proximal)

Condyler

Diarthrosis, sit in depression: radius-scaphoid, occipital-atlas, metacarpal/tarsal w/proximal phalange

saddle

Diarthrosis: thumb (metacarpal 1+trapezium)

Ball + Socket

Diarthrosis: hip (coxal/femur) and shoulder (humerous/scapula)

The RANK pathway

OPG blocks RANKL → less osteoclast activation → less bone breakdown

• RANK = receptor involved in osteoclast activation

• RANKL = binds RANK → promotes osteoclast formation/activation

• OPG = binds/blocks RANKL so it cannot activate RANK → decreases osteoclast activity

Estrogen role in rank pathway

Estrogen↑ → OPG ↑ → RANKL blocked → osteoclast activity ↓

what does menopause cause

decrease in estrogen which causes RANKL to not be blocked and increases osteoclast activity and increases osteoporosis risk

Denosumab

binds RANKL.

Therefore:

Denosumab → RANKL blocked → can't activate RANK → osteoclast activation ↓ → bone resorption ↓

what does prednisone do

↓ OPG

AND

↑ RANKL

Therefore:

↑ osteoclast formation/activity → ↑ bone resorption

But it ALSO causes:

osteoblast apoptosis → ↓ bone formation

So prednisone hurts bone from both directions:

More destruction + less rebuilding = bone loss