Bones, Muscles, and Skin

*The Human Body

*Organization of the Human Body

*http://www.youtube.com/watch?v=chqwSh4ii84&feature=related

*Organization of the Human Body

*Cells – the basic unit of structure and function*100 trillion in the adult human body*Play specific roles

*Tissues – a group of connected cells that have a similar function*Connective tissue – Form the bodies

structure*Bone and Cartilage

*Organization of the Human Body

*Types of Tissues*Epithelial tissue*Line the inner and outer body surfaces* Skin, lining of the digestive tract

*Protects the body and its internal organs* Secretes substances like hormones* Absorbs substances like nutrients

*Organization of the Human Body

*Tissues*Muscle Tissue*Have a unique ability to contract*Attached to bone allowing the body to move

*Nervous Tissue*Made up of neurons that carry electrical

impulses* Brain and nerves that connect the brain to all

other parts of the body

*Organs and Organ Systems

*An organ is a structure that consists of two or more types of tissues that work together to do the same job*Brain, lungs, heart, skin, kidneys*In Humans organs are organized into organ

systems*Work together to carry out a complex overall

function* Each organ does a part of a much larger job* http://www.youtube.com/watch?v=po8D290YF9o&#

38;feature=related

*The End Result

*A well-oiled machine*Closely controlled and regulated by the

nervous and endocrine systems*Nervous system does the controlling of the

body systems*The endocrine system secretes hormones that

regulate the activities*Functioning together they maintain

homeostasis* Temperature, pH, and other conditions at just the

right levels to support life

*Maintaining Homeostasis

*Respiratory System*A high concentration of carbon dioxide in the

blood triggers faster breathing.*The lungs exhale more frequently which removes

carbon dioxide from the body more quickly*Excretory System*Low level of water in the blood triggers

retention of water by the kidneys*Kidney’s produce more concentrated urine, so

less water is lost from the body

*Maintaining Homeostasis

*Endocrine System*High concentration of sugar in the blood

triggers secretion of insulin by the pancreas* Insulin helps cells absorb more sugar from the

blood stream

*Homeostasis Failure

*Cells may not get everything they need*Toxic wastes may accumulate in the body*Imbalance may lead to disease or even

death

*The Skeletal System

*All the bones of the body*In adults there are

206 bones*Cartilage provides a

smooth surface on which the joints can move*Ligaments hold bones

together

*The Skeletal System

*Functions*Protection of internal organs*Providing attachment surfaces for muscles*Producing blood cells*Storing minerals*Maintaining mineral homeostasis*Need just the right amount of calcium in the

blood for normal body functioning*Bones can absorb excesses

*Structure of Bones

*Very different from what we might think from looking at the bones of a skeleton*Bones are very much alive

*Structure of Bones

*Bone matrix*Compact and spongy bone*Tough protein fibers (collagen) that becomes

hard and rigid due to mineralization with calcium crystals

*Crisscrossed with blood vessels and nerves*Contains bones cells involved in metabolism*http://www.youtube.com/watch?

v=4qTiw8lyYbs

*Bone Cells

*Osteoblasts – make new bone cells and secrete collagen that mineralizes to become bone matrix*Bone growth*Uptake of minerals from the blood

*Osteocytes – regulate mineral homeostasis*Direct uptake of minerals from the blood

and the release of minerals back into the blood as needed

*Bone Cells

*Osteoclasts – dissolve mineral in bone matric and release them back into the blood*http://www.youtube.com/watch?v=yENNq

RJ2mu0&feature=related

*Bone Tissues

*Compact Bone*Makes up the dense outer layer of bone*Hard and strong

*Spongy bone*Found inside bones and is lighter and less dense

than compact bone because it is porous*Bone marrow*A soft connective tissue that produces blood cells*Found inside the pores of spongy bone

*Bone Tissues

*Periosteum*A tough, fibrous membrane that covers and

protects the outer surfaces of bones

*Growth and Development of

Bones

*Fetus – cartilage only*Will turn into hard bone by a process called

ossification*Mineral deposits replace the cartilage*By birth several area of cartilage remain* End of long bones* Remains as the bones grow

*Skeletal maturity reach by about age 20 and growth will stop*Will increase in thickness

*Bone Growth

*Joints

*A joint is where two or more bones meet*Immovable – allow no movement*Skull

*Partly moveable – allow very limited movement*Held together by cartilage*Ribs and sternum

*Moveable – allow the most movement*Connected by ligaments*Most common type of joint

http://www.youtube.com/watch?v=SOMFX_83sqk

*Joints

*Moveable*Also called synovial joints*Space between is filled with a thick fluid called

synovial fluid that cushions the joint*Ball and Socket – shoulder*Hinge – knee*http://www.youtube.com/watch?v=zWo9-3G

Jpr8&feature=related

*Skeletal System Problems

*Fractures – breaks in bone – heal when osteoclasts form new bone*http://www.youtube.com/watch?v=qVougiCEgH

8&feature=PlayList&*Osteoarthritis – cartilage breaks down causing

joint stiffness and pain*http://www.youtube.com/watch?v=F8YLJxiNh9Y*Rickets*http://www.youtube.com/watch?v=2ULfxsJKBuw

*The Muscular System

*Introduction

*Includes all of the muscles of the body*Made up of muscle cells which are also

called muscle fibers*These muscles fibers can contract or

shorten*No other cell in the body can do this*This is responsible for all movement of the

body both inside and out

*Types of Muscle

*Types of Muscle

*Smooth Muscle*Walls of internal organs like the stomach

and intestines*Helps the organs carry out their functions*These contractions are involuntary*They are not under conscious control

*Types of Muscle

*Skeletal Muscle*This type of muscle is attached to bone*Contractions of skeletal muscles are

voluntary*They are under conscious control*The most common type of muscle*More on this in a moment

*Types of Muscle

*Cardiac Muscle*Found in in the walls of the heart*When it contracts the heart beats and

pumps*Contains lots of mitochondria which

produces ATP for energy*Helps the heart resist fatigue

*Contractions are involuntary

*Skeletal Muscles

*Over 600 in the human body*Vary greatly in size*Contain hundreds to

thousands of muscle fibers*Surrounded by

connective tissue

*Skeletal Muscleshttp://www.youtube.com/watch?v=XoP1diaXVCIhttp://www.youtube.com/watch?v=uY2ZOsCnXIA&lr=1

*Skeletal Muscles and Bones

*Bones and muscles are connected by tendons*Muscles can only contract*So to move in opposite directions they must

work together to make that happen

http://www.youtube.com/watch?v=T-ozRNVhGVg&feature=related

*Use it or lose it

*Using skeletal muscles such as in weight lifting causes the muscle to increase in size and strength*Running increases the strength and

efficiency of cardiac muscle*Continual exercise is necessary to

maintain bigger, stronger muscles*If you don’t use muscle, it get smaller and

weaker

*Muscle Contraction

*Happens when muscle fibers shortens*Muscle Fibers*Contain organelles called myofibrils*Made up of two types of protein filaments* Actin (Thinner) and Myocin (Thicker)* Actin are connected to structure called Z lines* Region between two Z lines is called a sacromere* Actin and Myocin filaments overlap within the

sacromere* Myocin has tine structures called cross bridges that

can attach to actin fiber

*Sliding Filament Theory

*http://www.youtube.com/watch?v=7V-zFVnFkWg&feature=related

*Muscles and Nerves

*Muscles need a stimulus to contract*This message comes in the form of an

electrical nerve impulse from the brain to nerve cells called motor neurons*This neurons cause to muscle to perform the

action the is desired* (Involuntary contractions of cardiac and

smooth muscles are also controlled by nerves)

*The Integumentary

System

*Skin

*Integumentary system*Skin, hair, nails*Provide protective covering*Help maintain homeostasis*http://

www.youtube.com/watch?v=IAAt_MfIJ-Y

*Skin

*The largest organ in the body*1 Square inch of skin*20 blood vessels*650 sweat glands*1000+ nerve endings*60,000 pigment producing cells*On 2 mm thick*http://www.youtube.com/watch?v=uH_uzjY2b

EE&feature=fvw

*Epidermis and Dermis

*http://www.youtube.com/watch?v=d-IJhAWrsm0&feature=related

*Epidermis

*The outer layer of skin*Make up of epithelial cells and little else*No nerve endings or blood vessels*Innermost cells are continually undergoing

mitosis to form new cells*They move up through the layers as needed*Produce a tough, fibrous protein called keratin* Fill and then die by the time they reach the surface

* Form a protective waterproof layer called the stratum corneum

*Epidermis

*Contains melanocytes*Produce melanin – brownish pigment that

gives skin its color*Amount produced is determined by heredity* Increases due to exposure to UV radiation* Tanning* Also stimulates the skin to produce vitamin D

* Melanin prevents UV radiation from penetrating the skin

* Darker skinned people may be subject to a Vitamin D deficiency

*Dermis

*Lower layer of skin directly below the epidermis*Made of tough connective tissue and

attached to the epidermis by collagen fibers*Blood vessels and nerve ending*Hair follicles and two types of glands

*Dermis

*Hair follicles are when hairs originate – grow out of follicles and exit at the surface of the skin*Sebaceous glands – produce an oily

substance called sebum*Secreted into hair follicles and makes its way

to the surface*Waterproofs the hair and skin and helps

prevent them from drying out*Antibacterial as well

*Dermis

*Sweat glands*Produce the salty fluid called sweat*Contains excess water, salts, and other waste

products*Ducts that pass through the epidermis and

open to the surface of the skin through pores

*Functions of the Skin

*Preventing water loss*Barrier to the entry of microorganisms*Melanin blocks UV light and protects the

deeper layers of the skin from its dangerous effects*Regulate body temperature

*Skin Problems

*Acne*Pimples form on the skin due to bacterial

infection*Affects 85% of teens and may continue into

adulthood*Due to excessive secretion of sebum* Plugs hair follicles and makes them good breeding

grounds for bacteria* http://www.youtube.com/watch?v=11I7ONVqcc0

*Skin Problems

*Skin cancer*Skin cells grow out of control*Caused mainly by excessive exposure to UV

radiation*People with fair complexions are at greater

risk*Wear sunscreen and protective clothing

*Nails and Hair

*Nails – fingernails and toenails*Specialized epidermal cells that are filled

with keratin*Tough and hard*Fingernails also enhance sensations by acting

as a counterforce to the sensitive fingertips when objects are handled

*Nails and Hair

*Hair*Found only in mammals*Main component is keratin* Shaft is dead, keratin-filled cells that overlap each other

like shingles on a roof*Helps shed water

* Insulate and protect the body*Prevents heat loss*Eyelashes and eyebrows protect the eyes*Hairs in the nose traps dust and microorganisms

along with sensory input