THE HUMAN BODY

Bellwork 11/8 Why does our body sweat when we are hot or shiver when we are cold?

Maintaining Homeostasis Shivering occurs when your muscles rapidly contract and relax. Sweating helps to cool your body. Your internal body temperature will be close to 37 degrees C. If you become sick, you body temperature may rise but it will return to 37 degrees C when you are well again. This action produces heat that helps keep you warm.

Homeostasis The maintenance of a stable internal environment in the body in spite of changes in the external environment Constantly working to keep the body in balance Outside factors make this hard

Stress and Homestasis Stress- The reaction of your body to potentially threatening, challenging, or disturbing events Your heart may beat more rapidly Your breathing may increase Your endocrine system might release a chemical called adrenaline into your bloodstream Adrenaline gives your body burst of energy and prepares your body to take action Your muscles work harder and require more oxygen Oxygen is carried to the circulatory system Your heart then beats faster so that more oxygen can get into your body.

Body Organization Cells Tissues Organs Systems

Cells Building blocks of life Body is composed of billions of different cells When cells of the same type work together to do a job they form a TISSUE

Tissues

Four main types  Epithelial  Nervous  Muscle  Connective

Epithelial Tissues Cover and protect underlying tissue Skin for example

Nervous Tissue Send messages through the body Found in  Brain, nerves, and sensory organs

Muscle Tissue Made of cells that contract and relax Produce movement

Connective Tissue Many jobs  Joins/supports/insulates  Keeps organs from falling apart  Examples Bone and blood

Organs Two or more tissues working together form an ORGAN  Stomach uses all four types of tissues to perform digestion

Body Systems Organs working together form systems 12 major systems in the body Some organs are part of more than one system at a time

The Skeletal System

Skeletal System Made of bones, cartilage and the connective tissue that holds the bones together 206 in adults Multiple Functions

Functions of Skeletal System Protection Storage Movement Blood Cell Formation

Protection Prevents damage to organs  Skull protects brain  Ribcage protects heart, lungs, etc…  Spine protects spinal cord

Storage Minerals needed to help nerves and muscles work Long bones can store fat for energy

Movement Allow for places for muscles to attach Movement of skeletal muscles allow to move

Blood Cell Formation Marrow of some bones make cells of the blood

Bone Structure Made of connective tissue and minerals  Minerals deposited by cells called osteoblasts Two kinds of tissue  Compact bone and spongy bone

Bone Structure Compact Bone  Rigid and dense Spongy Bone  Many open spaces  Provide strength and support of bone

Bone Structure Bone Marrow  Soft tissue inside bone  Red marrow produces red and white blood cells  Yellow marrow stores fat

Bone Growth Bones start as cartilage and harden as you get older Tips of ears and nose the cartilage never gets hard

Joints Place where two or more bones meet Two major types of joints  Immovable  Movable

Immovable Joints Little or no movement is allowed Bones of skull are held together this way

Immovable Joints

Movable Joints Held together by connective tissue called ligaments Three Main Types  Gliding Joint  Ball-and-Socket Joint  Hinge Joint

Movable Joints Cartilage  Protective covering over ends of bones  Keeps bones from rubbing together

Gliding Joint Allow bones to move past one another  Found in hand and wrist

Ball-and-Socket Joint Allows for movement in many different directions Rotate at this joint  Shoulder  Hip

Hinge Joint Open and close like a door Knee Elbow

Muscular System

The Muscular System Made up of all the muscles that let you move Two Main Types  Involuntary  Voluntary

Involuntary Muscles Muscles that you do not have to think about to control Act on their own Important for:  Breathing, heart beating, blinking, etc…

Voluntary Muscles Muscles that you control with thought Movements  Smiling, speaking, raising your hand, walking, etc…

Muscle Tissue Three Types of Muscle Tissue  Smooth Muscle  Skeletal Muscle  Cardiac Muscle

Smooth Muscle Tissue Involuntary Muscle Makes up the inside of many organs Act without thought  Example: digestion in the stomach is automatic

Smooth Muscle

Skeletal Muscle Tissue Voluntary Muscles Attached to bones by tendons Responsible for moving Called striated muscles  Appear banded With lots of use become tired (fatigued)

Skeletal Muscle Tissue

Cardiac Muscle Found only in heart Is involuntary like smooth Striated like skeletal  Unlike skeletal it never gets tired

Cardiac Muscle Tissue

Muscles at Work Function by contracting Message from nervous system Work in pairs  When one muscle contracts its mate relaxes to its original length

Muscles at Work

Strength and Flexibility Some muscles can be made stronger and made to last longer  Regular exercise can help  Resistance and Aerobic Exercise

Integumentary System

Made up of skin, hair, and nails Covers the body and helps maintain homeostasis Skin is largest organ in body

Functions of Skin Protecting the Body Maintaining Temperature Eliminating Wastes Gathering Information Producing Vitamin D

Protecting the Body Forms a barrier  Keeps disease-causing microorganisms out Keeps important substances inside body  Prevents you from drying out

Maintaining Temperature Blood vessels in skin will enlarge when you get hot  Allows more blood to area and a temperature drop to occur Sweat glands produce perspiration

Eliminating Wastes Sweat contains waste materials Keeps some harmful materials from building up in your body This is why sweat is salty

Gathering Information Lots of nerve endings in skin As you touch things your body collects information  Pressure/pain/temperature Keeps you safe

Producing Vitamin D In presence of sunlight Important for healthy bones Helps cells to absorb calcium in food Only need a few minutes of sunlight each day

Layers of the Skin Two Main Layers  Epidermis  Dermis

Layers of the Skin

The Epidermis Outer layer Thinner than dermis No nerves or blood vessels Cells of epidermis (epithelial) are replaced about every 4 weeks

The Epidermis Outer layer is dead cells  This is what protects and cushions Shedding of dead cells carries away bacteria Melanin is produced in epidermis

The Epidermis Melanin protects skin by creating a tan when exposed to sun light Also cells in epidermis that produce fingernails

The Dermis Inner layer of skin Has:  Nerves/Blood Vessels/Sweat Glands/Hairs/Oil Glands Sweat and oil reach surface through pores

The Dermis Hair grow from follicles  Hair you see is made of dead cells Oil produced helps make hair waterproof and keep skin moist

Injuries, Disorders, and Diseases of the Skeletal System Fractures Postural Deformities Arthritis Cancer Osteoporosis Rickets

Fractures A fracture is any break in the bone About 6 different types  We will cover 3 Simple Greenstick Compound

Simple Fractures A clean break of the bone  Bone is often split into two pieces  No damage to skin  May result in bruising

Simple Fracture

Greenstick Fracture Bone is not completely broken  One side shows break  Other just bends Most commonly seen in children  Due to pliable nature of young bones

Greenstick Fracture

Compound Fracture Also known as an “Open” fracture Broken end of bone pushes out and breaks through skin Can result in damage to tissues and infection

Compound Fracture

Arthritis Inflammation of one or more joints Causes range depending on type of arthritis  Osteo arthritis is caused by wearing away of cartilage  Rheumatoid arthritis is caused when body attacks and breaks down cartilage (autoimmune disorder)

Rheumatoid Arthritis

Injuries, Diseases and Disorders of the Muscular System Sprains Strains Dystrophy

Sprains and Strains A sprain is when a ligament gets stretched too far  Symptoms of a sprain are: pain, swelling, and bruising of the affected joint A strain is an injury to a muscle or tendon, usually occurring when stretched too far  Can lead to muscle tears when a rip occurs in the muscle or tendon

Muscle Tear

Dystrophy Refers to a group of diseases All result in a wasting of the muscles  Loss of control  May extend to internal organs Leading to problems with organs functioning or even death

Injuries, Disorders, Diseases of Skin Hundreds of different problems can occur with the skin and underlying connective tissue Will look at just two  Acne  Psoriasis

Acne Term for pimples on the skin At puberty the oil glands of the skin start producing an oily material (sebum)  Sometimes the wall of the oil gland breaks and spills the sebum within the skin which causes redness, swelling, and pus (a pimple)

Acne

Psoriasis Causes are unknown Runs in families Results in areas of the skin growing much faster than others  Creates red and scaly patches that itch

Psoriasis

Can Happen On the Nails as Well