controlling system bloc 6 2011

8/22/2019 Controlling System Bloc 6 2011

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THE CORRELATION OF CONTROLLING SYSTEMS

WITH HOMEOSTASIS AND METABOLISM

ALWI SHAHAB

BLOC 6MARCH 2011


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1. Explain that the body is organized as a functional hierarchy from

the cell to tissues to organs to body systems to the individual.

2. Describe how the cell is the basic unit of life, and list itsfundamental requirements to survive.

3. The ultimate objective of this complexity is to maintain a stabileinternal environment (=homeostasis).

4. Describe the general mechanisms by which homeostasis isachieved.

5. Establish how a breakdown in homeostatic mechanisms can resultin sickness or disease.


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Living systems consist of a hierarchy ofcomplexity, starting with the basic unit of all lifethe cell.

Many cells of similar structure and function form atissue.

Different tissues form an organ and different organs

form a body system.

Each body system has one or more functions (e.g.,our integumentary system reduces water loss andprotects us from infection).

The eleven body systems work together to become anindividual.


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The eleven body systems :

1. Nervous System

2. Skeletal system3. Muscular system

4. Integumentary system

5. Circulatory system

6. Respiratory system

7. Digestive system

8. Excretory system

9. Endocrine system10. Reproductive system

11. Lymphatic/ Immune system


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Cell survival depends upon some basicrequirements, such as :-

consumption of oxygen,- release of carbon dioxide and nitrogenouswaste,

- breakdown of nutrients,- maintenance of ionic equilibria,- an ability to respond to local extracelluar

change,- and in some cases cell division.

These cellular requirements are reflected inthe air we breathe, the food we eat, and thewaste we excrete.


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A Stable Internal Environment Is Essential forNormal Cell Function


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Fluid compartments in the body.


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The body's fluids, is about 60% of the total body

weight, can be partitioned into 2 major

compartments :- the intracellular compartment

- the extracellular compartment.

The intracellular compartment, 40% of the body'sweight, is primarily a solution of potassium, other

ions, and proteins.

The extracellular compartment, 20% of the body

weight, is comprised of the interstitial fluids,plasma, and other fluids, such as mucus and

digestive juices, is primarily composed of NaCl

and NaHCO3.


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The living cells of our body, surrounded byan internal environment (extracellularfluid), communicate with the externalworld through this medium.

Exchanges of matter and energy betweenthe body and the external environment(indicated by arrows) occur via :- the gastrointestinal tract,

- kidneys,- lungs,- and skin (including the specialized

sensory organs).


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For optimal cell, tissue, and organ function ,

several facets of the internal environmentmust be maintained within narrow limits

These include to :

(1) Oxygen and carbon dioxide tensions,(2) Concentrations of glucose and other

metabolites,(3) Osmotic pressure,(4) Concentrations of hydrogen, potassium,

calcium, and magnesium ions, and(5) Temperature


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Homeostasis Is the Maintenance of Steady States in

the Body by Coordinated Physiological Mechanisms

Homeostasis in a general sense refers to stability,

balance or equilibrium.

Maintaining a stable internal environment requires

constant monitoring and adjustments as conditions

change.

This adjusting of physiological systems within the bodyis called homeostatic regulation.


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Homeostatic regulation

involves three parts or

mechanisms:

1) the receptor,

2) the contro l center,

3) the effector.


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Three Basic

Components:1. Receptor

detects change in avariable(stimulus/stress)

sends input(information) to acontrol center

2. Control Center assesses input; sends

output to effector(s)

3. Effector causes response, i.e.,

an effect which istriggered by output


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For example :

Our bodies control body temperature in a similar

way.

The brain is the control center

The receptor is our body's temperature sensors,

And the effector is our blood vessels and sweatglands in our skin.


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Pathways That Alter Homeostasis :

A variety of homeostatic mechanisms maintain the

internal environment within tolerable limits.

Either homeostasis is maintained through a series of

control mechanisms, or the body suffers various

illnesses or disease.


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When the cells in your body begin to malfunction, thehomeostatic balance becomes disrupted.

Eventually this leads to disease or cell malfunction.

Disease and cellular malfunction can be caused in two

basic ways:

- defic iency(cells not getting all they need)

- tox ic i ty(cells being poisoned by things they do not

need).


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When homeostasis is interrupted in your cells, there are

pathwaysto correct or worsen the problem.

In addition to the internal control mechanisms, there areexternal influences based primarily on lifestyle choices

and environmental exposures that influence our body's

ability to maintain cellular health.


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1. Nutr i t ion :

If our diet is lacking in a specific vitamin or mineral,

our cells will function poorly, possibly resulting in a

disease condition.

2. Tox ins :

Any substance that interferes with cellular function,

causing cellular malfunction.

This is done through a variety of ways; chemical,

plant, insecticides, and or bites.


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3. Psychological :

Our thoughts and emotions cause chemical changes totake place either for better as with meditation, or worseas with stress.

4. Physical:

Physical maintenance is essential for our cells andbodies.


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5. Genetic :

Inheriting strengths and weaknesses can be part of our

genetic makeup.

Beginning at the cellular level a variety of diseases come

from mutated genes cancer

6. Medical:

Through modern medicine our bodies can be given

different aids -from anti-bodies to help fight infectionsor chemotherapy to kill harmful cancer cells.


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Levels of biological organization :1. Chemical --> 2. Cell --> 3. Tissue --> 4. Organ --> 5. BodySystem --> 6. Individual


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The basic unit of life. The human body is an

assemblage of cells.

1. What are theproperties of a cell?

2. What do cells needin order to survive(and in turn whatdoes the human body

need in order tosurvive?)


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A general term used to identify an

aggregate of similar cells which

perform a specific function.

- Epithelial Tissue

- Connective Tissue

- Muscle Tissue

- Nerve Tissue


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Always lines either the external or internal

surface of the body.

Functions :

1) They secrete (endocrine glands)

2) They protect (outer layer of skin)

3) They absorb (lining of small intestine)


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Connective tissue has an extracellular maxtrix. Functions:1) Supportive (bone, cartilage)

2) Transport/Immunity (blood)3) Storage of nutrients (white fat)


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Muscle is an excitabletissue containingactin and myosinFunction:Movement throughcontraction of the cell.


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An excitable tissue.Function: Communication of information.Cell structure reflects this function.


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Various tissuescooperate to form anorgan which has aparticular functionin the body.


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A number of organs form a body system

(=organ system)-- each body system has a

specific function and most contribute to

achieving homeostasis.1. There are eleven body systems

2. Each body system helps maintain a

homeostatic cellular state.


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1. Negative feedback--its function is to keep a

physiological level relatively constant through time.Example: Regulation of Blood Pressure

2. Positive feedback. The sign changes from - to +.In this case feedback, accelerates a process which has

already started.Example: Regulation of blood clotting

3. Feedforward mechanismsExample: GLP-1/ GIP and Insulin stimulation/ glucagon

inhibition


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In negative feedback systems, the outputshuts off the original stimulus

Example: Regulation of blood pressure


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In positive feedbacksystems, the outputenhances orexaggerates the

original stimulus Example: Regulation

of blood clotting

Figure 1.6

F df d M h i


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Feedforward Mechanism

Glucose-dependent insulinotropic peptide (GIP)Glucagon like peptide-1 (GLP-1)

Insulin stimulationGlucagon inhibition


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Various regulatory systems are responsible for

homeostasis :

1. Neural regulationExample: Autonomic control of heart rate

2. Endocrine regulationExample: Insulin and Glucagon affect blood glucose level

3. Local autoregulation

Example: Effect of adenosine on cardiac vessels


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Summaries :

The regulation of the amounts of water and minerals in the body.

This is known as osmoregulation. This happens primarily in thekidneys.

The removal of metabolic waste. This is known as excretion. Thisis done by the excretory organs such as the kidneys and lungs.

The regulation of body temperature. This is mainly done by theskin.

The regulation of blood glucose level. This is mainly done by theliver and the insulin and glucagon secreted by the pancreas in thebody.

Most of these organs are controlled by hormones secreted fromthe pituitary gland, which in turn is directed by the hypothalamus.


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controlling system bloc 6 2011

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