* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Maintaining Homeostasis
Survey
Document related concepts
Transcript
Homeostasis Ch. 19 The Human Body – An Orientation • Anatomy – study of the structure and shape of the body and its parts • Physiology – study of how the body and its parts work or function Levels of Structural Organization Anatomy – Levels of Study • Gross Anatomy – Large structures – Easily observable • Microscopic Anatomy – Very small structures – Can only be viewed with a microscope Survival Needs • Nutrients – Chemicals for energy and cell building – Carbs, proteins, lipids, vit. & minerals • Oxygen - required for chemical reactions • Water – Provides for metabolic reaction – Stabilizing body temperature Homeostasis • Internal Equilibrium (or balance) • Maintenance of a stable internal environment = a dynamic state of equilibrium • Homeostasis must be maintained for normal body functioning and to sustain life • Homeostatic imbalance – a disturbance in homeostasis resulting in disease Maintaining Homeostasis • The body communicates through neural and hormonal control systems – Receptor are stimulated to: • Responds to the changes in the environment (stimuli) • Sends information to control center This is achieved mostly by the nervous system & the endocrine system Maintaining Homeostasis – The Control center: • Analyzes information that is received from the receptors (affector) • Determines the appropriate response – Effector • Provides a means for response to the stimulus (sends a reaction message to the effector) Feedback Mechanisms • Homeostasis is maintained in the body through Negative feedback – It works in response to a change that counteracts another change. – Its output response that affects the initial input feedback decreases its effect – Works like a household thermostat: it can shut off the original stimulus, or reduces its intensity – Includes most homeostatic control mechanisms Feedback Mechanisms • Positive feedback: – Is the opposite of negative feedback – It intensifies the original change by increasing the original stimulus to push the variable farther, rather than reversing itself to return to a set point. – In the body this only occurs in blood clotting and birth of a baby Homeostasis (Positive Feedback) Body Tissues • Cells are specialized for particular functions • Tissues – Groups of cells with similar structure and function – Four primary types • Epithelium • Connective tissue • Nervous tissue • Muscle Cell Diversity Cell Diversity Cell Diversity Cell Diversity Epithelial Tissues • Layers of tissue – Simple – one layer – Stratified – more than one layer • Found in different areas – Body coverings – Body linings – Glandular tissue • Functions – – – – Protection Absorption Filtration Secretion Classification of Epithelium • Shape of cells – Squamous – flattened – Cuboidal – cube-shaped – Columnar – column-like Glandular Epithelial Tissues • Cells that produce and release substance • Exocrine glands – Have ducts – Sweat glands, oil glands, salivary glands • Endocrine glands – Ductless – Produce hormones – Excrete hormone into the extracellular fluid & diffuse into nearby capillaries. – Pancrease: glucogon & insulin Connective Tissue Characteristics • Supports and binds other tissues • Variations in blood supply – Some types are well vascularized and other types have poor blood supply • Cartilage: flexible & resilient – Consists of spaced cells and extracellular matrix – a non-living material that surrounds living cells Cartilage tissue Connective Tissue Types • Bone (osseous tissue) is composed of: • Bone cells in lacunae (cavities) • Hard matrix of calcium phsophate Adipose Tissue • Insulates the body • Protects some organs • Serves as a site of fuel storage Connective tissue: Blood • 3 types of connective tissues in blood: – RBC – WBC – Platelets • Blood cells surrounded by fluid matrix called: Plasma Muscle Tissue • Function is to produce movement • Three types: Skeletal, Cardiac, Smooth muscle Nervous Tissue • Neurons and nerve support cells • Function is to send impulses to other areas of the body – Irritability – Conductivity Regeneration of Tissues • Tissues that regenerate easily – Epithelial tissue – Fibrous connective tissue and bone • Tissues that regenerate poorly – Skeletal muscle • Tissues that are replaced largely with scar tissue – Cardiac muscle – Nervous tissue within the brain and spinal cord The Skin Organ System Overview • Circulatory System (Cardiovascular) – Transports materials in body via blood pumped by heart • Carbon dioxide • Nutrients • Wastes – Includes heart, blood vessels Organ System Overview • Lymphatic System – Returns fluids to blood vessels – Disposes of debris – Involved in immunity • Includes lymph, lymph nodes & vessels, WBC Organ System Overview & blood • Digestive System – Breaks down food – Allows for nutrient absorption into blood – Eliminates indigestible material Includes: mouth, esophagus, stomach, sm. & lg. Intestines, anal, rectum Organ System Overview • Excretory/ Urinary System – Eliminates nitrogenous wastes – Maintains acid – base balance – Regulates water and electrolytes Includes: kidneys, ureters, bladder, urethra Organ System Overview • Respiratory System – Keeps blood supplied with oxygen – Removes carbon dioxide • Includes: nose, trachea, & lungs; (gills in fish & some amphibians) Organ System Overview • Endocrine System – Secretes regulatory hormones for: • Growth • Reproduction • Metabolism • Includes: various hormone secreting glands Organ System Overview • Nervous System – Fast-acting control system – Responds to internal and external change – Activates muscles and glands • Includes: brain, spinal cord, peripheral nerves Organ System Overview • Muscular System – Allows locomotion – Maintains posture – Produces heat – Contractibility • Includes: skeletal, cardiac & smooth muscle Organ System Overview • Skeletal System – – – – – – Protects internal organs Supports body structure Provides attachment site for muscles, so they can move Site of blood cell formation Stores mineral Bone is live and functional tissue • Includes: bones, cartilage, tendons & ligaments Organ System Overview • Integumentary System – Forms the external body covering – Protects deeper tissue from injury – Synthesizes vitamin D – Location of cutaneous (skin) nerve receptors • Includes: skin, hair, nails, Organ System Overview • Reproductive System – Production of – Spermatogenesis, • Includes: male/female offspring oogenesis reproductive organs – Penis, testes, seminal vesicles – Mammary glands, vagina, uterus, ovaries & oviducts Abdominopelvic Major Organs