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&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=yENNqRJ2mu0&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=zWo9-3GJpr8&feature=related

*Skeletal System Problems

*Fractures – breaks in bone – heal when osteoclasts form new bone

*http://www.youtube.com/watch?v=qVougiCEgH8&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_uzjY2bEE&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