EXAM 2 BIO 250 (Lecture slides)

Skeletal System 2 Divisions

1. Axial skeleton

2. Appendicular skeleton

Axial skeleton (Skeletal System 2 Divisions)

• skull

• vertebral column (spine)

• thorax (ribcage)

Appendicular skeleton (Skeletal System 2 Divisions)

• limbs (arms and legs)

• pelvic girdle

• shoulder girdle

Skeletal System Components

1. bones

2. cartilage

3. ligaments (bones to bones)

4. tendons (muscle to bones)

Skeletal System Functions

1. Supports body

2. Protects soft organs:

• brain, heart, lungs, spinal cord

3. Attachment for skeletal muscles

4. Stores minerals & fats:

• calcium, phosphorus, lipids

2 Types of Osseous (BONE) Tissues

1. Compact bone

2. Spongy bone

Compact bone (2 Types of Osseous (BONE) Tissues)

dense, smooth, homogeneous

Spongy bone (2 Types of Osseous (BONE) Tissues)

density varies, porous, heterogeneous

Long bones (Bones Classified by Shape)

• long shaft

• in limbs

Long bone examples (Bones Classified by Shape)

1. femur = thigh

2. humerus = UPPER arm

Short bones (Bones Classified by Shape)

mostly spongy

Short bone examples (Bones Classified by Shape)

1. carpals = wrist bones

2. tarsals = ankle “TALUS: singular”

3. sesamoid bones = INSIDE tendon

Sesamoid bone example [SHORT BONE] (Bones Classified by Shape)

patella = kneecap

Flat bones (Bones Classified by Shape)

• often CURVED, NOT COMPLETELY flat

• spongy bone BETWEEN 2 THIN layers of compact bones

Flat bone examples (Bones Classified by Shape)

1. skull

2. ribs

3. sternum = breastbone

Irregular bones (Bones Classified by Shape)

don’t fit in other categories

Irregular bone examples (Bones Classified by Shape)

1. vertebrae = backbones

2. pelvic bones

Diaphysis (Gross Anatomy of LONG Bones)

• LONG shaft of the bone

• MOSTLY COMPACT bone

Epiphyses (Gross Anatomy of LONG Bones)

Proximal & Distal

• MOSTLY SPONGY + THIN cover of COMPACT BONE

• articular cartilage

Epiphyseal PLATE (Gross Anatomy of LONG Bones)

• flat plate of HYALINE cartilage in YOUNG/GROWING bone

• makes long bone grow longer = growing taller!

Marrow(medullary) cavity (Gross Anatomy of LONG Bones)

INSIDE diaphysis

• yellow marrow in adults = mostly fat

• red marrow in infants = for hematopoiesis

Bone Components

bone = CONNECTIVE TISSUE (has extracellular matrix)

• HARD due to Ca salts in matrix

• FLEXIBLE due to collagen fibers in matrix

OSTEOcytes (Compact Bone Histology)

BONE cells

• lacunae: inside “shells” LACUNA: singular

Central (Haversian) canals (Compact Bone Histology)

tube at CENTER of OSTEON

• lengthwise thru bone

• vessels & nerves go thru it

Canaliculi (Compact Bone Histology)

TINY CANALS, connect central canal & lacunae

Canaliculi TRANSPORT (Compact Bone Histology)

• nutrients to osteocytes (glucose)

• waste from osteocytes

Ossification (Bone Formation & Growth)

deposition of bony matrix in long bones BEFORE BIRTH

OsteoBLASTS [Ossification] (Bone Formation & Growth)

bone-depositing cells

• swarm onto fetal skeleton made of hyaline cartilage

OsteoBLASTS digest away [Ossification] (Bone Formation & Growth)

cartilage skeleton

OsteoBLASTS deposit [Ossification] (Bone Formation & Growth)

hard bony matrix in its place

Ossification creates (Bone Formation & Growth)

medullary cavity in long bone

2 cartilages in long bones AFTER BIRTH that AREN’T REPLACED (Bone Formation & Growth)

1. articular cartilage

2. epiphyseal plate

Articular cartilage & Epiphyseal plates made of (Bone Formation & Growth)

hyaline cartilage

New cartilage grows ON (Bone Formation & Growth)

EXTERNAL faces of Articular/Epiphyseal cartilages

OsteoBLASTS digest old cartilage & deposit hard bony matrix ON (Bone Formation & Growth)

INTERNAL faces of Articular/Epiphyseal cartilages

Appositional growth (Bone Formation & Growth)

how long bones grow wider = increased diameter

• controlled by human growth hormone

Epiphyseal plate cartilage CONVERTED to (Bone Formation & Growth)

bony matrix at START of ADULTHOOD

• becomes epiphyseal line

• growth stops

Bone Remodeling happens throughout life due to: (Bone Remodeling)

1. Gravity = bearing weight

2. Exercise = muscles pulling on bones

3. Ca levels in blood

Calcitonin (Bone Remodeling)

• stimulus = INCREASED Ca level in blood

• effector = thyroid gland

• response = thyroid releases calcitonin

Calcitonin release activates (Bone Remodeling)

OsteoBLASTS: bone-depositing cells

• pull out Ca ions OUT of blood

• deposit Ca INTO bony matrix (bones)

OsteoBLASTS moving Ca from blood to bones leads to: (Bone Remodeling)

DECREASED Ca levels in blood = NEGATIVE FEEDBACK

Parathyroid hormone (PTH) (Bone Remodeling)

• stimulus = DECREASED Ca level in blood = HYPOcalcemia

• effector = parathyroid glands

• response = parathyroid releases PTH

PTH release activates (Bone Remodeling)

OsteoCLASTS = bone-dissolving cells

• dissolve Ca salts FROM bony matrix

• release Ca ions INTO blood

OsteoCLASTS dissolving Ca from bony matrix & releasing into blood leads to: (Bone Remodeling)

INCREASED Ca levels in blood = NEGATIVE FEEDBACK

2 Types (Bone Fractures)

1. Simple (closed) fracture

2. Compound (open) fracture

Simple (closed) fracture (Bone Fractures)

doesn’t penetrate skin

Compound (open) fracture (Bone Fractures)

penetrates out of skin

Treatment of Bone Fractures

1. Reduction

2. Immobilization

Reduction (Treatment of Bone Fractures)

• CLOSED reduction = bones MANUALLY placed back into position by physician

• OPEN reduction = bones secured SURGICALLY

Immobilization (Treatment of Bone Fractures)

bone placed in cast/splint while it repairs

How Body Repairs Bone Fractures:

1. Hematoma

2. Fibrocartilage callus

3. Bony callus

4. Bone remodeling

Hematoma forms (How Body Repairs Bone Fractures)

blood-filled swelling/bruise

Fibrocartilage callus forms (How Body Repairs Bone Fractures)

in a couple weeks

• cartilage matrix, bony matrix, & collagen fibers brought by blood to splint the break

Bony callus REPLACES (How Body Repairs Bone Fractures)

fibrocartilage callus

• osteoblasts deposit bony matrix = more weeks

Bone remodeling occurs (How Body Repairs Bone Fractures)

in response to mechanical stress AFTER cast/splint removed

• osteoblasts & osteoclasts do it

Tendons & ligaments are

AVASCULAR = poorly supplied with blood vessels

• often need surgery, unlike bones (repair themselves)

Articulations

joints

• where 2+ bones meet

Articulation Functions

1. hold bones in place

2. allow movement (most joints, NOT ALL)

Articulations are classified by:

function & structure

FUNCTIONAL Types of Joints

1. Synarthrosis

2. Amphiarthrosis

3. Diarthrosis

Synarthrosis (FUNCTIONAL Joints)

immobile

Amphiarthrosis (FUNCTIONAL Joints)

slightly mobile

Diarthrosis (FUNCTIONAL Joints)

freely mobile

STRUCTURAL Types of Joints

1. Fibrous

2. Cartilaginous

3. Synovial

Fibrous (STRUCTURAL joints)

• fibrous connective tissue between bones

• usually synarthrosis

Cartilaginous (STRUCTURAL joints)

• cartilage between bones

• usually amphiarthrosis

Synovial (STRUCTURAL joints)

• fluid-filled cavity between bones = fluid motion!

• diarthrosis

Synovial Joint 4 Structures (STRUCTURAL joints)

1. Articular cartilage

2. Articular capsule

3. Fluid-filled cavity = synovial fluid!

4. Reinforcing ligaments (bone to bone)

Synovial Joint Extra Structures [reduce stress/friction]

1. bursae

2. tendon sheaths

3. menisci

Bursae (Synovial Joint Extra Structures [reduce stress/friction])

flattened fibrous sacs

• lined w/ synovial membrane

• filled w/ synovial fluid

Tendon sheaths (Synovial Joint Extra Structures [reduce stress/friction])

elongated bursae wrapped around tendons

• tendons connect skeletal muscle to bone

Menisci (Synovial Joint Extra Structures [reduce stress/friction])

fibrocartilage discs in knee joints

• MENISCUS: singular

Synovial Joint Types:

1. Plane

2. Hinge

3. Pivot

4. Condylar

5. Saddle

6. Ball & Socket

Synovial Joint Directions of Movement

1. uniaxial

2. biaxial

3. multiaxial

Uniaxial (Synovial Joint Directions of Movement)

movement in 1 direction

Biaxial (Synovial Joint Directions of Movement)

movement in 2 directions

Multiaxial (Synovial Joint Directions of Movement)

movement in multiple directions

Uniaxial joint example:

elbow joint

Biaxial joint example:

radoiocarpal joint in wrist

Multiaxial joint example:

shoulder joint

Terms relating to Muscles (Muscular System)

1. myo

2. mys

3. sarco

Cardiac Muscle Control (Muscular System)

involuntary

Cardiac Muscle Location (Muscular System)

WALLS of HEART

Cardiac Muscle Function (Muscular System)

pumps blood through blood vessels

Cardiac Muscle Unique features of Fibers (cells) (Muscular System)

1. Intercalated discs

2. Striated (striped)

3. Short

4. Branched

Smooth Muscle Control (Muscular System)

involuntary

Smooth Muscle Location (Muscular System)

WALLS of hollow organs

• stomach, uterus, blood vessels, urinary bladder

Smooth Muscle Function (Muscular System)

PROPELS substances through organs

• food, urine, blood, sperm & egg

Smooth Muscle Unique features of Fibers (cells) (Muscular System)

1. NOT striated

2. Pointed at 2 ends

Skeletal Muscle Control (Muscular System)

voluntary

Skeletal Muscle Location (Muscular System)

attached to bones & skin

Skeletal Muscle Unique features of Fibers (cells) (Muscular System)

1. Multinucleate (>1 nucleus)

2. Striated (striped)

3. Long, straight cylinders

Skeletal Muscle FunctionS (Muscular System)

• movement

• maintain body position (posture)

• stabilize joints

• generate heat

• facial expressions

CT in Skeletal Muscles EXTERIOR to INTERIOR (Muscular System)

1. Fascia (Hypodermis) EXTERIOR

2. EPImysium

3. PERImysium

4. ENDOmysium INTERIOR

Fascia (Hypodermis) LOCATION [CT in Skeletal Muscles EXTERIOR to INTERIOR] (Muscular System)

BINDS muscle & skin

EPImysium LOCATION [CT in Skeletal Muscles EXTERIOR to INTERIOR] (Muscular System)

covering around whole skeletal muscle

PERImysium LOCATION [CT in Skeletal Muscles EXTERIOR to INTERIOR] (Muscular System)

covers fascicle (bundle) of muscle fibers

ENDOmysium LOCATION [CT in Skeletal Muscles EXTERIOR to INTERIOR] (Muscular System)

covers individual muscle fibers

Fascia (Hypodermis) TISSUE [CT in Skeletal Muscles EXTERIOR to INTERIOR] (Muscular System)

adipose CT

EPImysium TISSUE [CT in Skeletal Muscles EXTERIOR to INTERIOR] (Muscular System)

fibrous CT