Animal Structure/Physiological Process/Human Disease/Endocrine System
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- Cells
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Basic unit of life
There are approximately 75 trillion cells in the body
Cells are small because of surface area to volume ratio - Tissues
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Cells with similar function and structure make up a tissue
The four main types of tissues are epithelial, connective, muscle and nervous - Epithelial Cells
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Provide barrier between body surfaces and the environment
Allow for absorption and transport of fluids across the membrane
They surround body surfaces such as the blood vessals, bladder and gut - Epithelial Polarity
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There are two types of polarity: apical surfaces and basolateral surfaces
Apical surfaces face the environment or lumen
Basolateral surfaces face the blood
Different proteins are expressed in apical and basolateral membranes - Connective Tissue
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Allows for the connecting, anchoring and supporting of other tissues
Characterized by dispered populations of cells embedded in a non-living extracellular matrix - Muscle Tissue
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comprised of elongated cells specialized for contraction and generation of forces that cause movements of both internal body organs and body limbs
Most abundant tissue in the body
There are four main types which include smooth (gut, urinary tract), cardiac (pumps blood) and skeletal(moves the skeleton) - Nervous Tissue
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neurons that are specialized for the generation, conduction and processing of electricl impulses (action potentials)
Glial cells support the activity of neurons
Action potentials are passed to other neurons, muscle cells or endocrine glands - Relationship between tissues, organs and organ systems
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A collection of cells with the similar function and purpose is a tissue
A collection of tissues with the similar function and purpose is a organ
A collection of organs with the similar function and purpose is an organ system - Nervous System (Organs, Functions)
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Organs---brain, spinal cord, sensory organs, peripheral nerves
Functions--recieves, integrates, stores information and controls muscles and glands - Endocrine System (Organs, Functions)
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Organs--glands, pituraty, thyroid, parathyroid, pineal, adrenal, testes, ovaries, pancreas
Functions-a system of glands release chemical messages that control and regulate other tissues and organs - Muscle System
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Organs--skeletal muscle, smooth muscle and cardiac muscle
Functions-produces force and motion - Skeletal System
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Organs--bones
Functions--provides structural support for body - Basic Cellular Needs
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Eneergy procurement
Waste Elimination
Maintenance of Structure - Internal Environment
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Is maintained by the organ systems in the body
Body cells are bathed in an internal environment
The maintenance of the constancy of the internal environment is called homostasis - Body Fluid Compartments
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Contains the intercellular and extracellualr fluid
The extracellular fluid is composed of 80% interstital (tissue) fluid and 20% blood plasma
The extracellular fluid makes of 33% of total body water - Steady State
- Explains that the constancy of the internal environment requires energy
- The Circulatory System and the Internal Environment
- The circulatory system provides a vital link between individual cells and the sites of external exchange
- Homeostasis
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The regulated constancy of the internal environment
Provides theoretical framework for clinical medicine - Homeostatic Control
- Government by Diffusion/Osmosis, Ideal Gas Laws and the Laws of thermodynamics
- Laws of Thermodynamics
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1st law--energy can neither be created or destroyed (conservation of energy)
2nd law--energy flows toward increasing entropy (direction of flow)
Examples of the laws of thermodynamics are existent in exchange processes, life processes and social processes - Physiological Exchange Process
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Diffusion
Osmosis
Facilitated Diffusion
Active Transport - Mechanisms for Regulating Rates of Physiological Process
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Morphological or Anatomical Adaptations
Regulation by the Endocrine System
Regulation by the Nervous System - Diffusional Fluxes
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Efflux-is the outward flux
Influx-is the inward flux
Net flux-when the efflux is not equal to the influx - Fick's Law of Diffusion
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Jnet=influx-efflux=CAD/x
C=solute concentration difference (gm or moles/cm^3)
A=surface area acorss which diffusion is occuring (cm^2)
x=diffusion distance, ie. the thickness of the surface (cm)
D=diffusion coefficient (cm^2/sec) - Fick's Law Relationships
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The rate of flux is directly proportional to the concentration gradient, andarea of the exchange surface
Flux decreases as the thickness of the exchange surface increases - Osmosis
- Is the diffusion of water across a semi-permeable membrane from a less concentrated solution of solute to a more concentrated solution of solute
- Osmotic Pressure
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The hydrostatic pressure just to prevent water from traveling across the membrane
Important in the blood filtering by ther kidney - Facilitated Diffusion
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Facilitated Diffusion is the passive movement throug a membreane involving a specific carrier protein
Aids in the diffusion of polar substances
Carrier protein causes channel molecule to open
One example is insulin and glucose - Active Transport
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Energy dependent (ATP) transport of a subtance across membrane aganist the concentration gradient
There are three types which include uniport, symports, and antiports - Negative Feedback
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Te relationship of the response to the stimulus not in the direction of the response
For example a rise in blood glucose level detected by the pancreas will yield an increase in insulin which lowers blood glucose
These systems do not maintain absolute constancy
Examples include the thermostat, cruise control and toilet tank float - Positive Feedback
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Response and the stimuli are in the same direction
Not as common as negative feedback systems
Serves to amplify a weak stimuli
For example oxytocin in birth and drug addictions - Medicine
- Is described as an art, medicine, science and diagnsis, treatment and prevention of disease
- Cosmetic Dentistry
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Problem: chipped teeth and worn teeth
Solution: restoration with veneers and laminates - Medicine and Biology
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Biology and medicine mutually inform
-the knowledge of disease processes helps to inform about normal biological processes
-understanding biology leads to new drugs - Pathology
- the study of disease
- Disease
- A structural or functional change in the body judged to be abnormal
- Structural (organic) diseases
- Diseases characterized by structural changes in the body. Structural changes are called lesions.
- Functional diseases
- Disease onset has no associated structural changes. However, long-stnading functional diseases can result in structural changes
- Mortality
- causes of death
- Morbidity
- causes of disability
- International Classification of Disease
- A method used to define diseases
- Symptoms (manifestations of disease)
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Nature of data---patient's perceptions
Name for Collection of Results- History - Signs (manifestations of disease)
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Nature of Data--examiner's observations
Name for Collection of Results--physical examination - Laboratory Abnormalities (manifestations of disease)
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Nature of Data--results of tests and special procedures
Name for collection of results- laboratory findings - Pathogenesis
- The period between the normal state and the diseased state
- Prophylaxis
- The blocking of environmental factors such as brushing teeth
- Palliation
- Treatment of symptoms without curing disease
- Predictive testing
- Is made before the patient gets disease by looking at family history, etc.
- Diagnosis
- Is made when the patient has the disease
- Endocrine Cells
- secrete chemical messages (hormones) which bind to receptors on or in target cell
- Hormones
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secreted by endocrine cells
Autocrine hormones influence the cell that secretes them
Paracrine hormones influence nearby cells
Most hormones diffuse through the extracellular fluid, are picked up by the blood and distributed throughout the body - Endocrine Glands
- Vertebrates have nine endocrine glands which include the hypothalamus, pituitary, thyroid, parathyroid, pineal, thymus, adrenals, pancreas, ovaries and testes
- Target cells
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Those that respond to hormones because have the proper receptors
Can respond to hormones on the surface or inside the cell - What do hormones do?
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-Alter the rates of gene transcription-leading to the production of new protiens
-Alter the activity of pre-existing protiens-stimulating or inhibiting an already expressed activity
-Stimulates the rate of secretion of other hormones-trophic hormones - Types of hormones
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Water soluble-hydrophillic,lipidophobic, include peptide, protien and glycoprotein hormones, likely to go outside the cell
Fat-soluble hormones- hydrophobic,lipidphillic,steriod hormones,thyroid hormones,liely to go inside the cell - Endocrine Diseases
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Addison's Disease
Cushing's Disease
Diabetes (Type I) - Addison's Disease
- Insuffficient production of corticosteroids
- Cushing's Disease
- Overproduction of corticosteroids
- Diabetes (Type I)
- Pancreas fails to produce insulin so there is increased blood sugar and sweet urine. Must take insulin shots to control blood sugar
- Receptor Activiation
- when the binding of a hormone to a cell-surfacr receptor induces a conformational change in the receptor
- Transduction Pathway
- the sequence of events between the receptor activation and the initiation of the cellular response
- Water-Soluble Hormone
- -receptors are on the cell surface
- Fat-soluble hormones
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-includes sterioids
-steriods are produced on demand when the endocrine gland is stimulated
-move across the membrane
-once in the cell, steroid hormone can combine with nuclear or cytoplasmic receptors
-activitates gene transcription when binds to a chromosome - Gene Activiation
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-occurs when the steriod-receptor complex binds to a chromosome
-results in the production of new m-rna and ultimately new proteins in cells
- one example is the ovarian steriods which prepare the female for the developing embryo - Location of Hormone Receptors
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Plasma Membrane Bound
Cytoplasmic
Nuclear - Cell sensitivity to hormones
- can be altered by the up or down regulation of receptors in that cell
- Cholesterol
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all steroid hormones are derived from here
Needed for life
Basis of gluccocorticords, mineralcorticorticords and sex steriods - Hypothalamus
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Secretes releasing and release-inhibiting hormones as well as oxytocin and antidiuretics
It targets the anterior pituitary
Its important actions are to control secretion of hormones of the anterior pituitay and regulates the storing and releasing of hormones by the posterior pituitary
Is located in the brain - Anterior pituitary
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-secretes trophic and nontrophic hormones
-The trophic hormones it secretes includes thyrotropin, which targets the thyroid gland and stimulates synthesis and secretion of thyroxine
-Andrenocorticotropin targets the adrenal cortex and stimulates the release of hormones from the adrenal cortex
-Luteinizig hormones targets the gonads and stimulates the secretion of sex hormones from the ovaries and testes
-Follice-stimulating hormone which stimulates growth and maturation of eggs in females and sperm production in males
-Some of the nontropic hormones include the growth hormone and prolacin hormone - Posterior Pituitary
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-Releases oxytocin which targets the uterus, breasts and acts to induce birth by stimulating labor contractions and causes milk flow
-Releases antidiertic hormones which targets the kidney and stimulates water reabsoption and raises blood pressure - Thyroid
- Releases thyroxine which targets many tissues and stimulates and maintains cellular metabolism necessary for normal growth and development
- Parathyroids
- -Releases parathormone which targets the bone to absorbs bone and raises blood calcium
- Pancreas
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-Releases insulin which targets the blood, muscle, liver and fat; lowers blood sugar
-Releases glucagan which targets the liver and stimulates the breakdown of glycogen which raises blood sugar
-Somastostatin targets the digestive tract and decreases secretion, motality and absorpiton in the digestive tract by inhibiting insulin and glycogan release - Adrenal Medulla
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-Located in the kidney
-Is the core
-Releases epinephrine and noepinephrine which targets the heart, blood vessals and fat cells and stimulates flight or fight responses, increases the heart rate, raises blood sugar and redistributes blood to muscles - Adrenal Cortex
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-Releases glucorticoids which targts the muscles, immune system and other systems to mediate response to stress, reduces metabolism of glucose, reduce inflammation and immune response; example is cortisol
-Releases mineralocorticoids which target the kidney and stimulate excretion of potassium iions and reabsoption of sodium ions; example is aldosterone - Ovaries
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-Release estrogen which targets the breasts, uterus and stimulates the development and maintenance of female characteristics and sexual behavior
-Release Progesterone which targts the uterus and sustains pregency and helps maintain secondary sex characteristics - Testes
- -Release androgens which target various tissues and stimulate development and maintenance of males sex characteristics and sperm production
- Hormonal Control
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-Can take minutes to hours
-There is a delay between the release of hormone and the response of receptor - Neural Control
- -Response time is usually milliseconds