HUMAN BODY

•Climbing the walls? Spiderman is able to climb walls

•The explanation:

1.Hairs (called setae) on gecko’s toes contain split ends (called spatulae)

2. ability to “stick” to surfaces from attractions between molecules on the spatulae and the surface on which the gecko is crawling

– Correlation between structure and function– Human structure has a hierarchy:

• Cell• Tissues• Organs• Organ sytems

TISSUES

• groups of cells with a common structure and function• Main types:

– Epithelial– Connective– Muscle– Nervous

Epithelial tissue

• sheets of closely packed cells

• covers the body and lines the cavities and tubes of internal organs

• Functions in protection, secretion, and exchange

A  Simple squamous epithelium     (lining the air sacs of the lung)

B  Simple cuboidal epithelium     (forming a tube in the kidney)

C  Simple columnar epithelium     (lining the intestine)

D  Stratified squamous epithelium     (lining the esophagus)

Layers ofdead cells

Rapidly dividingepithelial cells

E  Stratified squamous epithelium     (human skin)

Connective tissue

• binds and supports other tissues

• various types

• characterized by sparse cells in an extracellular gel matrix

Cartilage-formingcells

Matrix

D. Cartilage     (at the end of a bone)

Centralcanal

Matrix

Bone-formingcells

E. Bone

F.BloodA. Loose connective tissue     (under the skin)

Collagenfiber

Cell

Collagenfibers

Cellnucleus

B. Fibrous connective tissue     (forming a tendon)

White bloodcells

Red bloodcell

Plasma

C. Adipose tissue

Fatdroplets

Muscle tissue

• functions in movement• Types:

– Skeletal muscle is responsible for voluntary body movements

– Cardiac muscle pumps blood– Smooth muscle moves the walls of internal

organs such as the stomach

Unit ofmusclecontraction

Musclefiber

Nucleus

A  Skeletal muscle

Nucleus

Musclefiber Junction between

two cells

Muscle fiberNucleus

C  Smooth muscle

B  Cardiac muscle

Cell body

Nucleus

Cell extensions

LM

33

0

Nervous tissue

• forms a communication network• the branching neurons transmit nerve signals that

help control body activities

• Artificial tissues have medical uses: can assist in the healing of several injuries

ORGANS

– Each organ is made of several tissues

– collectively perform specific functions

Small intestine(cut open)

Lumen

Epithelial tissue(columnar epithelium)

Connective tissue

Smooth muscletissue (2 layers)

Connective tissue

Epithelial tissue

Lumen

ORGAN SYSTEMS

• Organ systems work together to perform life functions1. Digestive 2. Respiratory3. Circulatory4. Lymphatic5. Immune6. excretory 7. Endocrine8. integumentary 9. Skeletal10.Muscular11.reproductive

– digestive and respiratory systems: • gather food and oxygen

A  Digestive system

Mouth

Esophagus

Liver

Stomach

Smallintestine

Largeintestine

Anus

B  Respiratory system

Nasal cavity

Larynx

Trachea

Bronchus

Lung

– The circulatory system, aided by the lymphatic system• Transports the food and oxygen

– The immune system• Protects the body from infection and cancer

C  Circulatory system

Heart

Bloodvessels

E  Lymphatic system

D  Immune system

Bonemarrow

Thymus

Spleen

Lymphnodes

Lymphvessels

– The excretory system • Disposes of certain wastes

– The endocrine and nervous systems• Control body functions

F  Excretory system

Kidney

Ureter

Urinarybladder

Urethra

Pituitary gland

Thymus

Thyroid gland

Testis(male)

Adrenal gland

Pancreas

G  Endocrine system

Ovary(female)

– The integumentary system• Covers and protects the body

– Skeletal and muscular systems• Support and move the body

I  Integumentary system

Hair

Skin

Nails

K  Muscular system

Skeletalmuscles

Cartilage

Bones

J  Skeletal system

– The reproductive system • Perpetuates the species

Female

Vasdeferens

Penis

Urethra

Testis

Prostategland

Male

Oviduct

Ovary

Uterus

Vagina

L  Reproductive systems

New imaging technology

• reveals the inner body without surgery

• X-rays: used for imaging bones and teeth• MRI, Magnetic resonance imaging: visualization

of soft tissues• MRM, Magnetic resonance microscopy: 3-D

images of very small structures

• CT, Computed tomography scans: excellent diagnostic tools

• PET, Positron-emission tomography: Yields information about metabolic processes at specific locations in the body

SKELETON

• human skeleton: 206 bones– axial skeleton:

• Skull• Backbone• rib cage

– appendicular skeleton:• bones of the arms and legs• and the joints where they

attach to the axial skeleton– pectoral or shoulder joint

– pelvic or hip joint

Skull

Examplesof joints

1

2

3

Clavicle

Scapula

Shouldergirdle

Sternum

Ribs

Humerus

Vertebra

Radius

Ulna

Pelvicgirdle

Carpals

Phalanges

Metacarpals

Femur

Patella

Tibia

Fibula

Tarsals

Metatarsals

Phalanges

– Movable joints• Provide the human skeleton with flexibility

1 2 3Ball-and-socket joint Hinge joint Pivot joint

Head ofhumerus

Scapula

Ulna

Humerus

Ulna

Radius

• Bones are complex living organs:– Cartilage at the ends of

bones: Cushions the joints- Bone cells, serviced by blood

vessels and nerves• Live in a matrix of flexible

protein fibers and hard calcium salts

– Long bones have a central cavity: to store yellow bone marrow, which is mostly stored fat

– Spongy bone contains red marrow: blood cells are made Cartilage

Bloodvessels

Fibrousconnectivetissue

Yellowbone marrow

Centralcavity

Compact bone

Spongybone(redbone marrow)

Cartilage

• Broken bones can heal themselves: re realigned and immobilized

– Artificial joints: often used to repair severe injuries

• Weak, brittle bones are a serious health problem, even in young people

• Osteoporosis, a bone disease characterized by weak, porous bones

• dynamic bone “remodeling” model: going on all the time: – osteoblasts

deposit bone – osteoclasts break

bone and release calcium

– As a person ages, the backbone and other bones tend to decline in mass; excessive bone loss is called osteoporosis

•The skeleton and muscles interact in movement:

Biceps contracted,triceps relaxed(extended)

Triceps contracted,biceps relaxed

Biceps

Triceps

Triceps

Biceps

Tendon

MUSCLES• Muscle cells are the

motors of the body• contractible proteins

fibers, myofilaments• with the proteins

actin and myosin

Muscle Fascicle

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Levels of Functional Organization in a Skeletal Muscle Fiber

Muscle Fiber

Myofibril

Sacromere

3 types:• Smooth muscle: walls of blood vessels

and the gut• Skeletal muscle: move the bones of the

skeleton• Cardiac muscle: fibers that branch and

interconnect to form a network connected, electrical impulses passes from cell to cell causing the heart to contract in an orderly fashion

• Skeletal muscles move the bones

• Tendons: connective tissue that attach muscles to bone

• Muscle tone: Even at rest, some of the motor units of muscles are always contracting= resting tension

• Athletic training increases strength and endurance: causes increases in:- number of mitochondria- concentration of glycolytic enzymes- glycogen reserves- myofibrils

Types of sports

fast or white fibers:• Large in diameter-densely

packed myofibrils

• Large glycogen reserves • few mitochondria

• Can contract in 0.01 sec following stimulation

• uses a lot of ATP• uses anerobic glycolysis:

converts stored glycogen to lactic acid

• fatigue rapidly because glycogen reserves are limited and lactic acid builds up

Slow or red fibers:• Only 1/2 the diameter of

fast fibers

• Takes 3 times longer to contract after stimulation

• abundant mitochondria

• Uses aerobic metabolism

• Has a more extensive capillary network

• Red color due to red pigment of myoglobin

• Muscles only pull because myofibrils contract:– muscles in the joints are attached in opposing pairs

called flexors and extensors – when contracted they move the bones in different

directions

• sliding filament model: muscular contraction– the head of a myosin filament binds to an

actin filament– ATP is used to flex the myosin head– when the muscle contracts, the myosin head

returns to its original shape and pulls the actin it is attached to along with it