Unit 4 Intro to Homeostasis Flashcards
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
Homeostasis is not but rather
A steady state or constant condition but a system constantly adjusted in response to changes in the environment
Examples of factors that affect homeostasis
Exercise
Fatigue
Extreme Temperatures
What are components that are monitored in homeostasis
Fluids and conditions
internal temperature
hormone level
pH
flow
glucose
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
Internal environment in body consists of what
Extracellular Fluid
Interstitial Fluid
Amount of extracellular fluid in adults - percentage of body mass it makes up
15 L; up to 20%
Causes of dramatic effects on cellular function
Volume, temperature and chemical composition changing quickly
Systems Involved in Homeostasis
Nervous
Endocrine
Muscular
Integumentary
Excretory
Reproductive
Nervous System Main Organs
Brain
Spinal Cord
Peripheral Nerves
Sensory Organs
Endocrine System Main Organs
Pituitary glands
Thyroid glands
Adrenal glands
Pancreas
Other hormone-secreting glands
Muscular System Main Organs
Skeletal Muscle
Cardiac Muscle
Smooth Muscle
Integumentary System Main Organs
Skin
Sweat Glands
Hair
Nails
Excretory System Main Organs
Kidneys
Bladder
Ureter
Urethra
Reproductive System Main Organs
Female: Ovaries, Oviducts, Uterus, Vagina, Mammary Glands
Male: Testes, Sperm Ducts, Accessory Glands, Penis
Nervous System Function
Receive sensory data from environment, informing body of external conditions
Transit signals throughout body based on those conditions to regulate homeostasis
Excretory System Function
Works to rid body of waste and maintains clean internal environment
Endocrine System Function
Regulates levels of various hormones essential to life processes
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
