Unit 4 Intro to Homeostasis Flashcards by Sugar Pie

Homeostasis Meaning

A state that the body is in when the internal physical or chemical conditions are in an acceptable or tolerable range suitable for essential biological processes

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Homeostasis is not but rather

A steady state or constant condition but a system constantly adjusted in response to changes in the environment

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Examples of factors that affect homeostasis

Exercise
Fatigue
Extreme Temperatures

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What are components that are monitored in homeostasis

Fluids and conditions
internal temperature
hormone level
pH
flow
glucose

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Examples of how body maintains homeostasis

-Pancreas regulates blood sugar levels
-Water evaporation regulates body temperature
-Kidneys maintain water balance
-Hypothalamus in brain regulates body temperature and changes in osmotic pressure
-Blood distributes heat in the body
-Skeletal muscles contract and release heat

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Internal environment in body consists of what

Extracellular Fluid
Interstitial Fluid

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Amount of extracellular fluid in adults - percentage of body mass it makes up

15 L; up to 20%

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Causes of dramatic effects on cellular function

Volume, temperature and chemical composition changing quickly

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Systems Involved in Homeostasis

Nervous
Endocrine
Muscular
Integumentary
Excretory
Reproductive

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Nervous System Main Organs

Brain
Spinal Cord
Peripheral Nerves
Sensory Organs

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Endocrine System Main Organs

Pituitary glands
Thyroid glands
Adrenal glands
Pancreas
Other hormone-secreting glands

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Muscular System Main Organs

Skeletal Muscle
Cardiac Muscle
Smooth Muscle

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Integumentary System Main Organs

Skin
Sweat Glands
Hair
Nails

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Excretory System Main Organs

Kidneys
Bladder
Ureter
Urethra

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Reproductive System Main Organs

Female: Ovaries, Oviducts, Uterus, Vagina, Mammary Glands
Male: Testes, Sperm Ducts, Accessory Glands, Penis

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Nervous System Function

Receive sensory data from environment, informing body of external conditions
Transit signals throughout body based on those conditions to regulate homeostasis

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Excretory System Function

Works to rid body of waste and maintains clean internal environment

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Endocrine System Function

Regulates levels of various hormones essential to life processes

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Circulatory System Function

Carries hormones and other chemicals throughout body

Immune System Function

Protects body from infections and fights infection when body has it

Liver Function

Controls amino acid levels
Detoxifies harmful chemicals
Manufactures important blood proteins

Integumentary System Function

Maintains constant body temperature

Feedback meaning

Cycle of events where a variable (i.e. body temperature, blood glucose level or blood pH) is continually monitored, assessed and adjusted

Three components of feedback

Sensor
Control Centre
Effector

Sensor Function

Detects a change in internal environment and sends a signal to control centre

Control Centre Function

Sets range of values within where a variable should be maintained, received information from the sensor and sends signals to effectors when needed

Effector Function

Receives signals from a control center and responds, resulting in a change to an internal variable

Four Conditions Monitored in Homeostasis

Blood Glucose Systolic Blood Pressure Temperature Blood pH

Blood Glucose (Normal Value, Factors that Influence it and How these factors influence it (increase or decrease))

-0.1% glucose -Exercise: Decreases -After eating: Increase

Systolic Blood Pressure (Normal Value, Factors that Influence it and How these factors influence it (increase or decrease))

-120 mm Hg -Exercise: Increases -Sleep: Decreases

Temperature (Normal Value, Factors that Influence it and How these factors influence it (increase or decrease))

-37 degrees Celsius -Exercise: Increases -Sleep: Decreases

Blood pH (Normal Value, Factors that Influence it and How these factors influence it (increase or decrease))

-7.35 -Exercise: Increa -After eating: Negligible effec

Negative Feedback meaning

Body works to reverse a change detected in a variable so that the variable is brought back to within a normal range

Negative Feedback occurrences

A sensor detects a change that disrupts a balanced state and signals a control centre Control centre activates an effector, reversing the change and restores the balanced state

Example of Negative Feedback

Sweating

How Sweating Works

Muscles produce heat, raising blood temperature, causing signals to be sent to control centre Control centre directs a response to several effectors (blood vessels and sweat glands) Blood vessels dilate, resulting in heat loss through radiation and conduction Sweat glands release heat Sweat evaporates from skin and heat is released from body Responses contiue until body temperature returns to normal

Talk about Homeostasis Regulation when Body Temperature is High

Coordinating Centre: Hypothalamus turns on cooling systems Regulator: Skin blood vessels dilate, increasing blood flow to skin and heat exudes from skin Sweat glands initiate sweating, evaporation of sweat causes cooling Result: Body temperature decreases; hypothalamus turns off cooling systems

Talk about Homeostasis Regulation when Body Temperature is Low

Coordinating Centre: Hypothalamus turns on warming systems Regulator: Skin blood vessels constrict, decreasing blood flow to skin and causing reduction in heat loss from skin Skeletal muscles contract; shivering generates heat production; body hair becomes erect to conserve heat Result: Temperature increases; hypothalamus turns off warming systems

Decreased Environmental Temperature Physiological Response and Adjustment

Physiological Response Constriction of blood vessels in skin Hairs on body erect Shivering Adjustment Heat is conserved More heat is generated by increased metabolism

Increased Environmental Temperature Physiological Response and Adjustment

Physiological Response Dilation of blood vessels of skin Sweating Adjustment Heat is dissipated

Positive Feedback Meaning

A change in variable tends to be strengthened or increased

Examples of Positive Feedback in Body

Blood Clotting Regulation of contractions during childbirth

Positive Feedback in Blood Clotting

After injury occurs, affected tissues release chemicals that activate platelets Platelets begin clotting process Release chemicals that stimulate further clotting until bleeding starts

Regulation of contractions during childbirth

When head of baby is in cervix, sensors are stimulated Impulses sent to brain (control centre), causing the pituitary gland to release oxytocin

Explain what happens in Regulation of contractions during childbirth

As uterus begins to contract, nerve impulses travel from birth canal to brain Brain triggers release of hormones from the pituitary gland, which enter the blood and increase the strength of uterine contractions Strong contractions stimulate brain to make even more hormones