Exam 2 - Anatomy & Physiology

Chapters 5, (skin), 6 (bone ), 7 (axial bone)

Integumentary System

• Largest system of the body (skin)

  Two Major Parts

• Cutaneous membrane (skin)

• Accessory structures

• made up of three layers, the epidermis, dermis, and the hypodermis

Cutaneous Membrane

(Skin)

Components include:

Epidermis (Outer Dermis) - superficial (On the surface) epithelium (tissue that line internal and external body surfaces; made up of cells)

Dermis (Inner Dermis) - Connective Issues

Accessory structures

• Originate in the dermis

• Extend through the epidermis to skin surface

• Hair and hair follicles

• Exocrine glands

• Nails

Integumentary Functions

• Protection of underlying tissues and organs

• Excretion of salts, water, and organic wastes

• Maintenance of normal body temperature

• Production of melanin: protection against uv light

• Production of keratin

• Synthesis of vitamin D3

• Storage of lipids

• Detection of touch, pressure, pain, etc.

• Coordination of the immune response

Skin Regeneration

takes 7-10 days for it to go from the lowest level to the top

Epidermis

• Stratified squamous epithelium

• Avascular, like all epithelia

• Contains Keratin

• Nutrients and oxygen diffuse from capillaries in the dermis

Dermis

• Located between epidermis and subcutaneous

• layer (middle layer of the skin)

• -Anchors epidermal accessory structures (e.g., hair follicles and sweat glands)

  Two components

• • Outer papillary layer

• • Deeper reticular layer

Subcutaneous Layer

(Hypodermis)

• Lies deep to dermis

• Connected to reticular layer by connective tissue

• stabilizes position of the skin

• Primarily adipose tissue

• Large arteries and veins are in superficial region

• Distribution of subcutaneous fat determined by sex hormones

• site of subcutaneous injections using hypodermic needles

Thick Skin

• Covers the palms of the hands and soles of the feet

• Has five layers of keratinocytes

Five Strata Layers

(of keratinocytes in thick skin): found in palms and soles

-From basement membrane to free surface

• Stratum basale

• Stratum spinosum

• Stratum granulosum

• Stratum lucidum

• Stratum corneum

Thin Skin

• Covers most of the body

• Has four layers of keratinocytes

Keratinocytes

(Cells of the Epidermis)

•The body’s most abundant epithelial cells

• Contain large amounts of keratin

Keratin

tissue found in hair, nails, and the skin outers layer. Can also be found in glands and organs

Four Layers of Thin Skin

• stratum basale

• stratum spinosum

• stratum granulosum

• stratum corneum.

Sinuses

Air-filled chambers in the skull

• Decrease weight of the skull

• Lined with mucous membranes, which

  produce mucus to moisten and clean the air

• Serve as resonating chambers in speech production

Paranasal sinuses

Air-filled chambers connected to nasal cavities

• Lighten skull bones

• Contain mucous epithelium

• Releases mucus into nasal cavities

Neck has how many cervical vertebrae?

7 cervical vertebrae

How many thoracic vertebrae does the upper back have?

12 thoracic vertebrae

• Each articulates with one or more pairs of

ribs

How many lumbar vertebrae does the lower back have?

Five lumbar vertebrae

How are vertebrae numbered?

By region, from top (superior) to bottom (inferior)

C1 articulates with skull, L5 with sacrum

Regions of the vertebral column

Cervical (C)

Thoracic (T)

Lumbar (L)

Sacral (S)

Coccygeal (Co)

C1 to C7

Small body (support only head)

Large vertebral foramen (largest part of spinal cord)

Concave superior surface

Anterior edge is inferior to posterior edge

All except C1 have spinous processes

Thoracic vertebrae (T1–T12)

Have heart-shaped bodies

Larger bodies and relatively smaller vertebral foramina than those in cervical vertebrae

Long, slender spinous process

Dorsolateral surfaces of body have costal facets

• Articulate with heads of ribs

Lumbar vertebrae (L1–L5)

Largest vertebrae

Thick, oval-shaped bodies

No costal facets or transverse costal facets

Triangular vertebral foramen

Superior articular processes face medially

Inferior articular processes face laterally

Slender transverse processes project dorsolaterally

Massive spinous processes

• For attachment of lower back muscles

Thoracic cage

The skeleton of the chest

• Thoracic vertebrae

• Ribs

• Costal cartilages

• Sternum

Functions of thoracic cage

• Protects organs of the thoracic cavity

  • Including heart, lungs, and thymus

• Provides attachment for muscles involved in:

  • Breathing

  • Maintaining position of vertebral column

  • Moving pectoral girdles

  • Ribs and sternum form rib cage

Ribs

• 12 pairs of long, curved, flat bones

• Extending from thoracic vertebrae

Ribs are divided into two type which are

• True ribs

• False ribs

What ribs are true ribs?

Ribs 1–7 are true ribs (Vertebrosternal ribs)

True ribs (vertebrosternal ribs) are connected to

the sternum by costal cartilages

What are false ribs?

Ribs 8–12 are false ribs and they do not attach directly to sternum

Vertebrochondral ribs (ribs 8–10)

• Costal cartilages fuse together

• Merge with cartilages of rib pair 7 before reaching sternum

Floating or vertebral ribs (ribs 11–12)

• Have no connection with the sternum

• Connect only to vertebrae and muscles of body wall

Sternum (breastbone)

A flat bone in anterior midline of thoracic wall

What are the three parts of the sternum?

• Manubrium

• Body

• Xiphoid process

Bone shapes

Sutural, Irregular, short, flat, long, sesamoid

Irregular Bones

Have complex shapes

ex: spinal vertebrae, pelvic bones

Flat bones

Thin with parallel surfaces

ex: bones of skull roof, sternum, ribs, and scapulae

Consists of spongy bone between 2 layers of compact bone (cortex)

within the cranium, the layer of spongy bone is called diploe

Long bones

Long and slender

Found in arms, legs, palms, soles, fingers, toes

Structures of the long bone

Diaphysis, Epiphysis, Metaphysis

Diaphysis

wall of compact bone

central space called the medullary cavity (marrow cavity)

(bone marrow)

Epiphysis

mostly spongy bone (trabecular bone)

Metaphysis

where the diaphysis and epiphysis meet

osteocytes

osteocytes (bone cells ) within lacunae organized around blood vessels

Bone cells

Make up only 2% of bone mass

4 types- osteogenic cells, osteoblasts, osteocytes, osteoclasts

Osteogenic cells

Mesenchymal cells that divide to produce osteoblasts

–Located in inner cellular layer of periosteum and in endosteum

–Assist in fracture repair

Osteoblast

Immature cells that produce new bone matrix during osteogenesis

• Osteoblast surrounded by bone matrix Become osteocytes

Osteocytes

Mature bone cells that do not divide

Live in lacunae between layers of matrix

Have cytoplasmic extension that pass through canaliculi

• Maintain protein and mineral content of matrix

• Help repair damaged bone

Osteoid

Matrix produced by osteoblast that has not yet become calcified

Osteoclasts

Absorb and remove bone matrix

Large, multinucleate cells

Secrete acids and protein-digesting enzymes (dissolve bone matrix and release stored minerals, this osteolysis is important in homeostasis)

Derived from the same stem cells that produce monocytes and macrophages

Ossification(osteogenesis)

Bone formation

Two forms of ossification

• Endochondral ossification - How bones form

• Intramembrous ossification - Occurs in dermis

  Produces dermal bones suck as mandible(lower jaw) and clavicles(collarbones)

Calcification

Deposition of calcium salts

Occurs during ossification

Bone remodeling

Occurs throughout life

Functions in bone maintenance (recycling and renewing bone matrix)

Involves osteocytes, osteoblasts, and osteoclasts

Normally activities are balanced

Effects of exercise on bone

Mineral recycling allows bone to adapt to stress

Heavily stressed bones become thicker and stronger

Excercise particularly weight bearing exercise, stimulates osteoblasts

Bone degeneration

Bone degenerates quickly

Up to one third of bone mass can be lost in a few weeks of inactivity

hormonal effect on bone

Growth hormone and thyroxine stimulate bone growth

Sex hormones (estrogen and testosterone stimulate osteoblasts

Parathyroid hormone and calcitonin maintain calcium ion homeostasis

Nutritional effects on bone

Vitamin C is required for collagen synthesis and stimulates osteoblast differentiation

Vitamin A stimulates osteoblast activity

Vitamin K and B12 are required for synthesis of bone proteins

Minerals needed

Minerals calcium and phosphorus are required in the diet

Skeleton as a calcium reserve

Bone store 99% of the body’s calcium in addition to other minerals

Calcium is the most abundant mineral in the body

Calcium ions are vital to many physiological processes

Hormones and calcium ion balance

Calcium ion concentrations in body fluids must be closely regulated (8-11: normal range)

Parathyroid hormone and calcitonin affect storage absorption, and excretion of calcium ions in bones, digestive tract, kidneys

Parathyroid hormone (PTH)

Produced by parathyroid glands in neck

PTH increases blood calcium ion levels by

• Stimulating osteoclast activity (indirectly)

• Increasing intestinal absorption of calcium by enhancing Calcitirol secretion by kidneys

• Decreasing calcium excretion by kidneys

Calcitonin

Secreted by C cells in thyroid

Calcitonin decreases blood calcium ion levels by

• Inhibiting osteoclast activity

• Increasing calcium excretion and reducing Calcitirol secretion by kidneys decreasing intestinal absorption of calcium

With age bone becomes

Thinner and weaker

Fractures

Cracks o breaks in bones due to physical stress

Open(compound) or closed (simple)

Major types of fractures

Transverse, displaced, compression, spiral, epiphyseal, comminuted,greenstick, colls,Potts

Osteopenia

Inadequate ossification (reduction of bone mass)

Begins ages 30 and 40

Women lose 8% bone mass per decade men lose 3%

Results in fragile limbs, reduced height, and tooth loss

Osteoperosis

Severe loss of bone mass

Over age 45 occurs in 29% of women 18% of me.

Hormones and bone loss

Sex hormones help maintain bone mass

In women osteoporosis accelerates after menopause

transverse fracture

Break is in a straight line across the bone.

Displaced fracture

The ends of the bone have come out of alignment

Compression fracture

Bone is crushed, causing it to look wider or flatter

Spiral fracture

Break spirals around the bone (twisting injury)

• call cps

Epiphyseal fracture

affects the growing part of a child’s bone

Comminuted fracture

Bone has broken into 3 or more pieces and fragments are present at fracture site.

Greenstick fracture

Incomplete fracture, a portion of the bone is broken causing the other side to bend.

Coll’s fracture

Break in the radius close to the wrist.

Potts fracture

Fractures around the ankle

Where cant CPR be done and why?

low on sternum, because it will rupture

spinal/vertebral column

Clavicle(collarbones)

S-shape

Articulate with scapulae(acromial end)

Scapulae(shoulder blades)

Broad, flat triangles

Articulate with humerus and clavicle

Where to find elastic cartilage in the body?

External ears, Eustachian tubes, Larnyx