The Integumentary System:The Skin

The Integumentary System

Integument is skin Skin and its appendages make up the

integumentary system A fatty layer (hypodermis) lies deep to it Two distinct regions

EpidermisDermis

Skin

Your skin is your largest organ It is your first line of defense against

disease and damage It is made of several layers

Functions of skin

Protection Cushions and insulates and is waterproof Protects from chemicals, heat, cold, bacteria Screens UV

Synthesizes vitamin D with UV Regulates body heat Prevents unnecessary water loss Sensory reception (nerve endings)

Layers of Skin

Epidermis Uppermost layer of skin

Contains dead and living cells New cells are replaced daily old ones slough off

(they shed) Dermis-

Inner thicker layer of skin Contains:

Blood vessels Nerve receptors Hair follicles Sebaceous glands

Sweat glands Oil glands Wax glands

Remember…

Four basic types of tissue

Epithelium – epidermis just discussedConnective tissue - dermisMuscle tissueNervous tissue

Dermis Strong, flexible connective tissue: your “hide” Rich supply of nerves and vessels Critical role in temperature regulation (the

vessels) Two layers (see next slides)

Papillary – includes dermal papillae- makes fingerprints

Reticular – “reticulum” (network) of collagen and reticular fibers

Skin Layers

Subcutaneous Layer- lies below the dermis layer, not really a skin layer

Contains Fat cells Fibers used to attach skin to muscle

*Dermis layers

*

*

*Dermal papillae

Skin Color

Skin pigmentsMelanin- dark skin pigment (causes human skin

colors)Where there are darker colors on the skin there

is a higher concentration of melanin in that area Freckles Moles birthmarks

Skin color Three skin pigments

Melanin: the most importantCarotene: from carrots and yellow vegiesHemoglobin: the pink of light skin

Melanin Variations in colorProtection from UV light by producing vitamin

D

How does our skin protect us?

Forming callus- a thickened area of epidermis caused

by rubbing or pressureBlisters- area of skin when the layers of skin

separate due to excessive friction or intense heat

Melanin produces vitamin D- “natural sunblock”

Sweat glands Prevent overheating 500 cc to 12

Liters/day! (is mostly water)

Humans most efficient (only mammals have)

Produced in response to stress as well as heat

Fingerprints, palmprints, footprints Dermal papillae lie atop dermal ridges Elevate the overlying epidermis into epidermal ridges Are “sweat films” because of sweat pores Genetically determined

Flexion creases Deep dermis, from continual folding

Fibers Collagen: strength and resilience Elastic fibers: stretch-recoil

Striae: stretch marks Tension lines (or lines of cleavage)

The direction the bundlesof fibers are directed

The dermis is the receptive site for the pigment of tattoos

Disorders of the integumentary system Burns

Threat to life Catastrophic loss of body fluids Dehydration and fatal circulatory shock Infection

Types First degree – epidermis: redness (e.g. sunburn) Second degree – epidermis and upper dermis: blister Third degree - full thickness

Infections Skin cancer

BurnsFirst-degree(epidermis only; redness)

Second-degree(epidermis and dermis,with blistering)

Third-degree(full thickness, destroying epidermis, dermis, often part of hypodermis)

SKELETAL SYSTEMSKELETAL SYSTEM

BONES & JOINTSBONES & JOINTS

Functions of the Bones

1. Support2. Protection3. Movement4. Storage (minerals like calcium and phosphorous)

5. Hematopoiesis (makes new blood cells in the bone marrow)

Fig. 6.21

Bones The adult human skeleton has 206 bones Bones store minerals (calcium) and make blood

cells (in the center of the bone, bone marrow) Are made of mineral deposits of calcium and

phosphorous There small spaces that contain blood vessels

(veins, arteries, and capillaries) The blood vessels and surrounding bone

materials makes up an osteon (bone cell)

Broken Bones• A broken bone is a fractured bone:

• Bones can break in many ways:• Incomplete fracture- when there is only a crack, but

not a break• Complete fracture- when the bone breaks completely

in two• Comminuted fracture- fractures that splinter the

bone

J O I N T S

JOINTS

= a site where 2 or more bones = a site where 2 or more bones

come together with or without come together with or without movementmovement

JOINTS

1. Hinge joints 1. Hinge joints = bend in only one direction, like a door hinge= bend in only one direction, like a door hinge

flexion & extension movements possibleflexion & extension movements possible e.g.: elbow, kneee.g.: elbow, knee

2. Gliding Joints-2. Gliding Joints-= allows bones to slide across one another, and = allows bones to slide across one another, and

allows allows some twisting movementsome twisting movement

Like the bones between the vertebraeLike the bones between the vertebrae3. 3. Ball & socket joints Ball & socket joints

= = ball – shaped head of one bone fits into a ball – shaped head of one bone fits into a socket – like concavity of anothersocket – like concavity of another

= free movements possible:= free movements possible:e.g. shoulder and hipe.g. shoulder and hip

4. Pivot Joint- 4. Pivot Joint-

=allows for some circular movement=allows for some circular movement

e.g. The two bones of the forearm near the elbowe.g. The two bones of the forearm near the elbow

5. 5. FFused Joints-used Joints-

= = do not allow any movementdo not allow any movement

They become permanently fused togetherThey become permanently fused together

e.g. Bones of the skulle.g. Bones of the skull

Joints

Muscles

My muscles are important because they… Hold my organs in place Hold my bones together

so that I can move Help me chew my food Open and close my

eyelids Pump my blood Allow me to run and

play Help me to smile!

Muscles & the Skeleton Skeletal muscles cause the skeleton to

move at joints They are attached to skeleton by

tendons. Tendons transmit muscle force to the

bone. Tendons are made of collagen fibres &

are very strong & stiff

Functions of the Muscular System

The characteristics of muscle tissue enable it to perform some important functions, including:

Movement – both voluntary & involuntary

Maintaining posture

Supporting soft tissues within body cavities

Guarding entrances & exits of the body

Maintaining body temperature

Muscular System

This system is responsible for movement of the body:But it cannot do this alone. Help is required

from the nerves, joints, and bones. –They work together as an orchestra, each

playing their part in perfect harmony

Muscles work by pulling never pushing

Muscular System

Muscles are responsible for all types of body movement

3 basic muscle types are found in the bodySkeletal muscleCardiac muscleSmooth muscle

Types of Muscles

Voluntary: muscles you can control, they are subject to one’s willSkeletal muscles- move your skeleton/bonesHave striations- they have a banded pattern,

appears layered

Characteristics of the Skeletal Muscles

Most are attached by tendons to bones

Striated – have visible banding

Voluntary – subject to conscious control

Anatomy of skeletal muscles

Skeletal muscle fiber (cell)

Muscle Fascicle

Surrounded by perimysium

Surrounded by endomysium

endomysium

perimysium

Skeletal muscle

Surrounded by epimysium

epimysium

tendon

Play IP Anatomy of Skeletal muscles (IP p. 4-6)

Characteristics of Cardiac Muscle

Similar to skeletal muscle cardiac muscle has striations

These striations are not as pronounced in cardiac muscles as in skeletal muscle

It is the only involuntary muscle that is striated

Found only in the heart

Smooth Muscle CharacteristicsSmooth Muscle Characteristics• Has no striations

• Involuntary – no conscious control

• Found mainly in the walls of hollow organs

• Stomach, intestines, blood vessels, and other internal organs

• The heart is involuntary, but not smooth muscle

• Slow, sustained and tireless

• They are constantly in motion and do not tire as do skeletal muscles

Smooth Muscle

Comparison of Muscle Tissue

How Muscles Work

Skeletal muscles work in pairsWhen your bicep contracts your triceps relaxWhen the triceps contract your bicep relaxes

Many skeletal muscles extend across at least one joint to 2 different bonesThe Sartorius (longest muscle in body)

attaches to the top of the hip bone and extends across the hip and knee connecting to the tibia

How Muscles Work

Some muscles do not extend across joints but rather movement in skin or other musclesTongue and throat muscles do not extend

over joints but they move to allow swallowing

Sternoclediomastoid

Frontal

Temporalis

MasseterObicularis orisObicularis oculi

Functions of Muscles Muscles keep you warm by contracting

When you are cold your body shivers in an attempt to warm you up by increasing muscle contractions and thereby producing heat

They keep your body erect (standing up)Even when you are still, standing or sitting,

your muscles are working and thereby can keep your body warm

This is why yoga is so effective in working muscles, prolonged muscle contractions

More Muscle Functions

When muscles in your skin contract making the hair follicles stand upright your skin around the hair follicle also stands up and causes…Goose bumps

Goose Bumps

How Muscles Work

Muscles need energy to function, so where does that energy come fromEnergy is stored in the body as glucose

(sugar) It is carried by the blood to the muscles where

the muscles break down the glucose into usable energy

In order to break down glucose the body needs oxygen

How Muscles Work

When the muscles break down sugar, with the use of oxygen, it is aerobic respirationThe oxygen comes to the muscles from the

lungs via arteries so that they muscles can break the sugar down into usable energy for the body

How Muscles Work

When you work or play hard, like when running, you begin to breathe faster in attempts to bring more oxygen into your blood so that your muscles can continue to work (break down sugar)

When you do not have sufficient oxygen your muscles undergo lactic acid fermentation producing lactic acid in the muscles

How Muscles Work

A build up of lactic acid in your muscles causes them to become sore or cramp up …have you gotten tired or sore muscles the

day following a hard workout or a day of hard play?

This is also how you get a Charlie horse