HUMAN HUMAN BODYBODY

CH. 34 - CH. 34 - 3939

Chapter Chapter 3434 Protection, Support, Protection, Support,

and Locomotionand Locomotion

Skin: The Body’s ProtectionA.A. Structure & Functions of Integumentary Structure & Functions of Integumentary

SystemSystem– Integumentary system consists of layers of Integumentary system consists of layers of

the four types of body tissues:the four types of body tissues: 1) 1) epithelial tissueepithelial tissue - outer layer of skin - outer layer of skin 2) 2) connective tissueconnective tissue - tough & flexible - tough & flexible

protein fibers that act to hold body protein fibers that act to hold body together together

3) 3) muscle tissuemuscle tissue - interact w/ hairs on skin - interact w/ hairs on skin & respond to stimuli like cold and fright& respond to stimuli like cold and fright

4) 4) nervous tissuenervous tissue - detects external - detects external stimuli like pain and pressurestimuli like pain and pressure

Main organ in integumentary Main organ in integumentary system is the system is the skinskin, which makes it , which makes it the largest organ in the body since the largest organ in the body since it is 12-15% of body weight!it is 12-15% of body weight!–Made of two layers:Made of two layers:

EpidermisEpidermis: outer layer of skin: outer layer of skinDermisDermis: inner layer of skin: inner layer of skin

Layers of SkinLayers of Skin

• EpidermisEpidermis– outermost layer of skin made of 2 parts: outermost layer of skin made of 2 parts:

exteriorexterior and and interiorinterior portions portions ExteriorExterior: 25-30 layers of dead, flattened cells : 25-30 layers of dead, flattened cells

that are continually being shedthat are continually being shed– Even though dead, are important since contain Even though dead, are important since contain

keratinkeratin which helps protect living cells underneath which helps protect living cells underneath

InteriorInterior: living cells that continually divide to : living cells that continually divide to replace dead cellsreplace dead cells

– Contain pigment Contain pigment melaninmelanin that colors skin and that colors skin and protects it from damage by solar radiationprotects it from damage by solar radiation

Melanin is not sole protector for sun damage – Melanin is not sole protector for sun damage – can get skin cancer if are dark pigmented!can get skin cancer if are dark pigmented!

– process of shedding takes 28 days (4 weeks)process of shedding takes 28 days (4 weeks)

• DermisDermis– Inner, thicker portion of skinInner, thicker portion of skin– Contains many structures:Contains many structures:

Blood vessels (arteries & veins)Blood vessels (arteries & veins)Nerves & nerve endingsNerves & nerve endingsHair folliclesHair folliclesSweat glandsSweat glandsSebaceous (oil) glandsSebaceous (oil) glandsMuscles (to make hair stand up)Muscles (to make hair stand up)

– Beneath dermis is subcutaneous layerMade of fat and connective tissue

–Help body absorb impacts, retain heat, store food

• Functions of Integumentary Functions of Integumentary SystemSystem

– Four main functions:Four main functions: 1. 1. Maintains homeostasisMaintains homeostasis

– Regulates internal body temperatureRegulates internal body temperature When temperature rises, small When temperature rises, small

blood vessels in dermis dilate blood vessels in dermis dilate (increase in circumference), (increase in circumference), allowing blood flow to increase, so allowing blood flow to increase, so blood loses heatblood loses heat

When temperature lowers, blood When temperature lowers, blood vessels constrict (decrease in vessels constrict (decrease in circumference), decreasing blood circumference), decreasing blood flow, so blood keeps in heatflow, so blood keeps in heat

Feedback loop:Backward/forward

Feedback LoopFeedback LoopInternal Body Temperature

ChangesBlood vessels

dilateBlood vessels

constrict

Blood flow increases

Blood flow decreases

Blood loses heat

Blood keeps in heat

Internal Body Temperature Normalizes

+ -

2. 2. sensory organsensory organ–Nerve cells get information from

external environment about pain, pressure, and temperature and send message to brain

3. produces Vitamin D–When exposed to UV light, skin makes

Vitamin D, which is essential to help body absorb calcium Most calcium supplements contain

Vitamin D for that same reason 4. protective layer

– Shields underlying tissues from Shields underlying tissues from physical and chemical damage and physical and chemical damage and from invading microbes (viruses and from invading microbes (viruses and bacteria)bacteria)

B.B. Skin injury and HealingSkin injury and Healing– Injuries to skin can occur due to scrapes, cuts, or Injuries to skin can occur due to scrapes, cuts, or

burns but how skin heals depends on severityburns but how skin heals depends on severity Mild scrape (no blood, epidermis only)Mild scrape (no blood, epidermis only)

– Deepest layer of affected epidermal cells start to divide to fill in gap left by abrasion

Cut (blood, epidermis and dermis)Cut (blood, epidermis and dermis)– Blood flows out of wound until clot forms– Scab develops, creating barrier b/t bacteria

on skin and underlying tissues Bacteria already present in wound gets

killed by white blood cells that migrate to site

– New skin cells begin repairing wound from beneath

Large wound needs high amount of connective tissue which may form a scar

Healing of a CutHealing of a CutBefore

Cut in skin

Blood pools, creating scab

Skin cells regenerate from bottom up

Burn (sun, chemicals, hot objects)Burn (sun, chemicals, hot objects)– First degree (mild sunburn)First degree (mild sunburn)

Death of epidermal cells Redness and mild pain Heal in 1 week w/out scar

– Second degreeSecond degree Damage of both epidermal and dermal cells Blistering and scaring may occur

– Third degreeThird degree Destruction of both epidermal and dermal

cells Skin function is lost, so skin grafts are

required– Fourth degreeFourth degree

Destruction through skin and into muscles, tendons, ligaments, and bone

11stst Degree Burn Degree Burn

22ndnd Degree Burn Degree Burn

33rdrd Degree Burn Degree Burn

A. Skeletal System Structure – Adult human skeleton contains 206 Adult human skeleton contains 206

bones! Made of two main parts:bones! Made of two main parts: Axial skeletonAxial skeleton: skull and bones that : skull and bones that

support it like vertebral column, ribs, support it like vertebral column, ribs, sternumsternum

Appendicular skeletonAppendicular skeleton: bones of : bones of arms and legs (appendages), and all arms and legs (appendages), and all structures associated with them structures associated with them (shoulder, hips, wrists, ankles, fingers, (shoulder, hips, wrists, ankles, fingers, toes)toes)

Ch. 34.2 - Bones: The Body’s Support

Axial vs. Appendicular Axial vs. Appendicular SkeletonSkeleton

– Bones meet other bones at areas called Bones meet other bones at areas called jointsjoints Joints facilitate movement of bones in Joints facilitate movement of bones in

relation to one anotherrelation to one another– Joints can be fixed (non-moveable) or Joints can be fixed (non-moveable) or

non-fixed (moveable)non-fixed (moveable) Fixed jointsFixed joints: skull: skull Non-fixed jointsNon-fixed joints: knee, wrist, etc.: knee, wrist, etc.

- 4 types of moveable joints:- 4 types of moveable joints:* * Ball-and-socketBall-and-socket: hips, : hips,

shouldersshoulders

* * PivotPivot: twisting arm at : twisting arm at elbowelbow

* * HingeHinge: elbows, knees, : elbows, knees, fingers, toesfingers, toes

* * GlidingGliding: wrists, ankles: wrists, ankles

Types of Joints Found in Types of Joints Found in HumanHuman

Types of Joints Found in Types of Joints Found in HumanHuman

Joints are held Joints are held together by ligamentstogether by ligaments– LigamentLigament: tough : tough

band of connective band of connective tissue that attaches tissue that attaches one bone to anotherone bone to another Joints with a large Joints with a large

range of motion range of motion (knee) have many (knee) have many ligamentsligaments

Ends of joints are Ends of joints are covered in covered in cartilagecartilage– Allows for Allows for

smooth smooth movement b/t movement b/t bonesbones

Certain joints have Certain joints have fluid-filled sacs fluid-filled sacs called called bursaebursae ((bursabursa is singular) is singular)– Outside of joint b/t Outside of joint b/t

tendon and bone tendon and bone to reduce friction to reduce friction

Muscles are Muscles are attached to bones attached to bones with with tendonstendons – Are thick bands Are thick bands

of connective of connective tissuetissue

JOINTS JOINTS

BONE

CARTILAGE

LIGAMENT

JOINT

MUSCLE

TENDON

Joints can become Joints can become diseaseddiseased– ArthritisArthritis: :

inflammation of inflammation of the jointsthe joints Bone spurs are Bone spurs are

outgrowths of outgrowths of bone inside bone inside the joints so it the joints so it limits mobility limits mobility

Types of Bone Types of Bone are two types of bone tissue:are two types of bone tissue:

– Compact boneCompact bone and and spongy bonespongy bone Compact boneCompact bone: hard bone that : hard bone that

contains tubular structures called contains tubular structures called osteonsosteons or or Haversian systemsHaversian systems– Surrounds spongy bone to protect itSurrounds spongy bone to protect it

Spongy (cancellous) boneSpongy (cancellous) bone: less : less dense bone with many holes and dense bone with many holes and spacesspaces

– Living bone cells are called Living bone cells are called osteocytesosteocytes, , which receive oxygen and nutrients from which receive oxygen and nutrients from small blood vesselssmall blood vessels

Types of Bone Types of Bone

B.B.Formation of BoneFormation of Bone Skeleton of human embryo is actually Skeleton of human embryo is actually

made of made of cartilagecartilage, not bone (same as , not bone (same as what nose is made out of)what nose is made out of)– Not until embryo is 9 weeks does Not until embryo is 9 weeks does

cartilage get replaced by bonecartilage get replaced by boneWhen blood vessels penetrate When blood vessels penetrate cartilage membrane, stimulate it cartilage membrane, stimulate it to become to become osteoblastsosteoblasts (precursors to osteocytes)(precursors to osteocytes)

How do How do osteoblastsosteoblasts become become osteocytesosteocytes??– Osteoblasts secrete protein Osteoblasts secrete protein

collagencollagen– Minerals like calcium and other Minerals like calcium and other

ions (found in bloodstream) are ions (found in bloodstream) are deposited in collagendeposited in collagen

– Osteoblasts are now osteocytesOsteoblasts are now osteocytes

Osteoblasts to OsteocytesOsteoblasts to Osteocytes

osteoblast

osteocyte

collagen

+ +&

Calcium

ions

BoneBone

OsteocytesOsteocytes

Human skeleton is almost 100% bone, Human skeleton is almost 100% bone, with cartilage found only in places with cartilage found only in places where flexibility is needed – nose, ears, where flexibility is needed – nose, ears, vertebral disks, and joint liningsvertebral disks, and joint linings

Bone grows in length and diameter as Bone grows in length and diameter as result of sex hormones released during result of sex hormones released during growth growth – LengthLength: from cartilage plates at ends of : from cartilage plates at ends of

bonesbones– DiameterDiameter: from outer surface of bone: from outer surface of bone

After growth stops, bone-forming cells After growth stops, bone-forming cells are involved in repair and maintenance are involved in repair and maintenance

C.C. Skeletal System Skeletal System FunctionsFunctions Function of skeleton is five-fold:Function of skeleton is five-fold:

– 1. Provide framework for tissues of body1. Provide framework for tissues of body Allows muscles to attach to bones so they can Allows muscles to attach to bones so they can

provide movement to bodyprovide movement to body– 2. Protects internal organs2. Protects internal organs– 3. Produce blood cells3. Produce blood cells

Red marrowRed marrow: where red blood cells, white blood : where red blood cells, white blood cells, blood clotting factors are producedcells, blood clotting factors are produced

– found in humerus, femur, sternum, found in humerus, femur, sternum, ribs, vertebrae, pelvisribs, vertebrae, pelvis

– 4. Store fat4. Store fat Yellow marrowYellow marrow: many other bones store fat in : many other bones store fat in

herehere– 5. Mineral storage5. Mineral storage

Body’s supply of calcium and phosphate is Body’s supply of calcium and phosphate is stored in bonestored in bone

Skeleton is vulnerable to injury and diseaseSkeleton is vulnerable to injury and disease– Broken bonesBroken bones

Too much force against bone can Too much force against bone can cause it to break or fracturecause it to break or fracture

– Physician must set bone back in place so Physician must set bone back in place so new osteocytes may form in broken area new osteocytes may form in broken area and put two ends back togetherand put two ends back together

– OsteoporosisOsteoporosis Loss of bone volume and mineral Loss of bone volume and mineral

content which leads to bones content which leads to bones becoming more porous and brittle and becoming more porous and brittle and more susceptible for breakagemore susceptible for breakage

– More common in older women since they More common in older women since they produce lower amounts or estrogen which produce lower amounts or estrogen which aids in bone formationaids in bone formation

Fracture TypesFracture Types

Fracture TypesFracture Types

A.A. Three Type of MusclesThree Type of Muscles – Nearly half of body mass is Nearly half of body mass is musclemuscle!!

MuscleMuscle: groups of fibers, or cells, : groups of fibers, or cells, bound together. Almost all muscle bound together. Almost all muscle fibers have been present since birthfibers have been present since birth– 3 main types of muscle:3 main types of muscle:

Smooth muscleSmooth muscle: walls of : walls of internal organs and blood vesselsinternal organs and blood vessels

Cardiac muscleCardiac muscle: heart muscle: heart muscle Skeletal muscleSkeletal muscle: muscles : muscles

attached to bonesattached to bones

Ch. 34.3 – Muscles for Locomotion

Muscle TypesMuscle Types

Muscle TypesMuscle Types

Smooth MuscleSmooth Muscle– Made up of sheets of cells that form Made up of sheets of cells that form

a lining for organsa lining for organs– Most common function is to squeeze Most common function is to squeeze

via contractions, exerting pressure via contractions, exerting pressure on space inside tube or organ to on space inside tube or organ to move material inside itmove material inside it Ex: food bolus gets squeezed through Ex: food bolus gets squeezed through

digestive system until it comes out; digestive system until it comes out; sperm gets squeezed through vas sperm gets squeezed through vas deferens, then urethra until it comes deferens, then urethra until it comes outout

Movement of Smooth Movement of Smooth MuscleMuscle

Contraction (AKA peristalsis)

Item to be moved

Direction of movement

Smooth muscle of vessel or organ

• Contractions are involuntary (can’t be controlled by human) so muscle is considered to be an involuntary muscle

Cardiac MuscleCardiac Muscle

– Found in heart and is adapted to generate Found in heart and is adapted to generate and conduct electrical impulses!and conduct electrical impulses!

– Considered an Considered an involuntary muscleinvoluntary muscle

– Muscle that is attached to and moves Muscle that is attached to and moves bonesbones

– Makes up majority of muscles in body Makes up majority of muscles in body which work in opposing pairswhich work in opposing pairs Muscle X on one side of bone, Muscle Muscle X on one side of bone, Muscle

Y on other side of boneY on other side of bone– If Muscle X is contracted, Muscle Y If Muscle X is contracted, Muscle Y

is relaxed, and vice versais relaxed, and vice versa– Considered a Considered a voluntary musclevoluntary muscle since since

contractions can be controlledcontractions can be controlled How do we contract our muscles? How do we contract our muscles?

Skeletal MuscleSkeletal Muscle

Opposing Muscle PairsOpposing Muscle Pairs

Muscle Contracted

Muscle Relaxed

Muscle Names Muscle Names

B.B. Skeletal Muscle Skeletal Muscle ContractionContraction All muscle tissue is made of muscle All muscle tissue is made of muscle

fibersfibers, which are very long, fused , which are very long, fused muscle cellsmuscle cells– Each fiber is made of smaller units Each fiber is made of smaller units

called called myofibrilsmyofibrilsMyofibrils made of thick and thin Myofibrils made of thick and thin filamentsfilaments– Thick filaments: Thick filaments: myosinmyosin

– Thin filaments: Thin filaments: actinactin Myofibril can be divided into Myofibril can be divided into segments called segments called sarcomeressarcomeres

Muscle Muscle ContractionContraction

ActinMyosin

Relaxed Sarcomere

Z Disc

– How do muscles contract? How do they How do muscles contract? How do they know that you want to “make a muscle?”know that you want to “make a muscle?” Sliding Filament TheorySliding Filament Theory

Sliding Filament TheorySliding Filament Theory Sliding filament theorySliding filament theory: when signaled, : when signaled,

actin filaments within each sarcomeres slide actin filaments within each sarcomeres slide toward one another, shortening sarcomeres toward one another, shortening sarcomeres in a fiber and causing muscle to contractin a fiber and causing muscle to contract– Myosin fibers do NOT moveMyosin fibers do NOT move– When skeletal muscle receives a signal (via When skeletal muscle receives a signal (via

brain), calcium is released inside muscle brain), calcium is released inside muscle fibers, causing two sides of sarcomere to fibers, causing two sides of sarcomere to “slide” toward each other = “slide” toward each other = contractioncontraction

– When signal is gone, calcium gets When signal is gone, calcium gets absorbed, sarcomeres relax and slide away absorbed, sarcomeres relax and slide away into placeinto place

Sliding Filament TheorySliding Filament Theory

Contracted Sarcomere

Yellow = actin (thin)Pink = myosin (thick)

Black = Z disk

C.C. Muscle Muscle StrengthStrength and and ExerciseExercise Muscle strength does not depend on Muscle strength does not depend on

amount of fibersamount of fibers but does depend on but does depend on thickness of fibersthickness of fibers– You are born with the number of fibers You are born with the number of fibers

you will always have, but exercise can you will always have, but exercise can increase thickness of each fiber increase thickness of each fiber making entire muscle biggermaking entire muscle bigger Exercise stresses muscle fibers slightly, so Exercise stresses muscle fibers slightly, so

to compensate for workload, fibers to compensate for workload, fibers increase in diameter by increase in diameter by adding myofibrilsadding myofibrils

Energy that muscles Energy that muscles need to contract comes need to contract comes from ATP produced by from ATP produced by cellular respiration cellular respiration (aerobic and anaerobic (aerobic and anaerobic processes)processes)– Most energy comes Most energy comes

from aerobic from aerobic respiration when respiration when oxygen (from oxygen (from breathing) is breathing) is delivered to muscle delivered to muscle cells during rest or cells during rest or MODERATE activityMODERATE activity

– During VIGOROUS activity (when we During VIGOROUS activity (when we have tendency to hold our breaths & have tendency to hold our breaths & delivery of oxygen is not as fast as it delivery of oxygen is not as fast as it needs to be), anaerobic respiration needs to be), anaerobic respiration kicks in and in addition to ATP being kicks in and in addition to ATP being made, lactic acid fermentation makes made, lactic acid fermentation makes lactic acid which makes muscles lactic acid which makes muscles cramp upcramp upLactic acid build up gets sent into Lactic acid build up gets sent into bloodstream, where triggers rapid bloodstream, where triggers rapid breathing (panting!)breathing (panting!)

Inhalation of oxygen again breaks Inhalation of oxygen again breaks down lactic acid & cramps go awaydown lactic acid & cramps go away

Lactic Acid Build Up Lactic Acid Build Up (During Vigorous (During Vigorous

Exercise)Exercise)