Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology 🦠 > Chapter 9: Homeostasis > Flashcards

Chapter 9: Homeostasis Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is homeostasis

A
  • it is the maintenance of a constant internal environment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why does the body need to regulate body temoerature

A
  • enzymes can only work within a certain range of temperatures
  • if the body’s temperature is higher than the specific temperature, the enzymes will denature
  • if too low, the enzymes will be inactive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why does the body need to regulate water potential in blood?

A
  • if water potential in blood is higher than cell, then water will move to cells
  • cells will expand, swell and burst
  • if water potential in blood is lower then cells, water will move out of cell.
  • cell will shrink and crenate and die
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why does the body need to regulate blood glucose concentration

A
  • cells in body need glucose to undergo cellular respiration and release energy to perform their vital activities
  • it is dangerous if blood glucose levels drop below normal levels for too long
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Negative feedback loop

A
  • stimulus in body (change in internal environment)
  • receptors detect stimulus
  • nerve impulses are sent to control centre
  • corrective mechanism occurs
  • condition returns to normal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is negative feedback

A
  • the sequence of events that take place in the body to restore the system back to its original state
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens when water potential in blood rises above normal

A
  • water potential in blood increase due to large intake of water
  • hypothalamus stimulated
  • less ADH released by pituitary gland into bloodstream
  • less ADH transported to kidneys
  • cells in walls of collecting duct becomes less permeable to water
  • less water reabsorbed into blood stream
  • more water excreted
  • urine more diluted
  • more urine is produced
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens when water potential in blood drops below normal

A
  • water potential in blood drops due to sweat/dehydration
  • hypothalamus stimulated
  • more ADH is released by the pituitary gland into blood stream
  • more ADH transported to kidneys
  • cells in walls of collecting duct becomes more permeable to water
  • more water reabsorbed into the blood stream
  • less water excreted
  • urine is more concentrated
  • less urine produced
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Hormone

A
  • a chemical substance produced in minute quantities by an endocrine gland. it is transported in the bloodstream to target organs where it exerts its effects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do hormones control human body

A
  • hormones can influence the growth, development & activity of an organism
  • they are chemical messengers that help the various parts of the body to respond, develop and work tgt smoothly
  • they are produced by endocrinologists glands & secreted directly into the bloodstream
  • glands with ducts are called exocrine gland
  • the pancreas is both an endocrine and exocrine gland
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Endocrine gland (ductless glands)

A

Hypothalamus: regulates secretion of some hormones
Pituitary gland: plays important role as a “controller”. it secretes a number of hormones, which control the secretion of hormones of several other endocrine glands. is is known for being the “master gland”. It also secretes ADH
Pancreas: Islets of Langerhans in pancreas secrete insulin and glucagon
Ovary: secretes oestrogen and progestrone
Testis: secretes testosterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens when normal amount of insulin is secreted

A
  • it decreases blood glucose concentration
  • makes cell surface membranes more permeable to glucose, allowing more glucose to diffuse into the liver and muscle cells
  • stimulates liver and muscle cells to convert excess glucose into glycogen for storage
  • increases use of glucose for respiration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens when lack of insuline is secreted

A
  • increases blood concentration
  • glucose cannot be stored or utilised by tissue cells
  • hence blood concentration rises, some glucose is last in urine
  • gives rise to diabetes
  • muscle cells have no reserve of glycogen, body grows weak and continuously lose weight
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens when too much insuline is secreted

A
  • abnormal decrease in blood glucose concentration
  • low blood glucose concentration results in condition called shock
  • seizures or fits, collapsing or passing out may follow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Effects of glucagon

A
  • islets of langerhans increase secretion of glucagon when concentration of blood glucose is below normal
  • main target organ is liver
  • increases blood glucose concentration
  • stimulates conversion of glycogen into glucose
  • stimulates conversion of fats and amino acids into glucose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens when blood glucose concentration is above normal

A
  • blood glucose concentration rises above normal
  • islets of langerhans in pancreas are stimulated
  • islets of langerhans secretes more insulin into blood stream
  • blood transports insulin to the liver and muscles
  • insulin increases permeability of cell membrane to glucose
  • glucose is absorbed more readily by cell
  • insulin increases rate of respiration
  • insulin causes the live and muscles to covert excess glucose to glycogen, which is stored tin liver & muscles
  • blood glucose concentration decreases
  • provides negative feedback to receptor to reduce insulin production
17
Q

What happens when blood glucose concentration falls below normal

A
  • blood glucose concentration falls below normal
  • islets of langerhans in pancreas are stimulated
  • islets of langerhans secretes more glucagon into blood stream
  • blood transports glucagon to liver and muscles
  • glucagon causes the conversion of glycogen back to glucose
  • from liver, glucose enters the bloodstream
  • blood glucose concentration increases
  • provides negative feedback to receptor to reduce glucagon production
18
Q

What is diabetes mellitus

A
  • a disease in which the body is unable to control its blood glucose concentration in order for it to remain within normal limits
  • blood glucose concentration can rise to a level that exceeds kidney’s ability to complete reabsorb all the glucose
  • glucose that is not reabsorbed is excreted via urine
  • type 1 diabetes develops early in a person’s life where the islets of langerhans are unable to produce are secrete enough insuline. it is inherited
  • type 2 occurs later in life and develops when the target cells no longer respond well to insulin
19
Q

Signs of diabetes

A
  • persistently high blood glucose levels
  • presence of glucose in urine
  • healing of wounds is slow and difficult
  • frequent urination
  • weight loss
  • thirst
20
Q

How can diabetes be treated

A
  • diabetics have to measure their blood glucose concentrations and test their urine regularly
  • they must also watch their diet, making sure that they do not take in too much carbohydrates
  • people with type 1 diabetes have to inject insulin regularly into the fat tissue under the skin
  • if they use too much insulin, exercise too much or eat too little, their blood glucose concentration can drop too low and they may go into a coma
  • they need to be ready with a supply of sugary foods
  • they should also take medication that increases uptake of glucose from blood stream into cells
21
Q

Risk factors of type 2 diabetes

A
  • when liver and muscle cells do not respond well to insulin
  • risk factors include obesity, age, family history, blood lipid levels (if you have high levels of bad cholesterol & low levels of good cholesterol), and sedentary lifestyle
22
Q

How to avoid type 2 diabetes

A
  • eat healthily
  • engage in more active physical activity
  • avoid being inactive for long periods of time
  • maintain a healthy body weight based on age and height
23
Q

Structures in skin involved in temperature reulation

A
  1. Arteriole
  2. Blood capillaries
  3. Hair follicle
  4. Hair
  5. Hair erector muscle
  6. Sweat gland
  7. sweat duct
  8. sweat pore
  9. nerve endings (thermoreceptors)
  10. adipose tissues
24
Q

Blood vessels under skin surface

A
  • dilatation and constriction of arterioles are caused by the contraction and relaxation of muscles in arteriole walls
  • contraction and dilation of arterioles help regulate body temperature
  • when arterioles vasodilation, more blood is sent to the blood capillaries in the skin. the skin becomes red because of the numerous blood vessels in the skin dialate
  • vasoconstriction of arterioles reduces amount of blood flowing through capillaries in skin & cause us to be pale
25
Q

Sweat glands

A
  • secreted sweat flows through sweat duct to sweat pore that opens at skin surface
  • secreted sweat consist of water, dissolved salts and small amounts of urea
  • sweat is secreted continuously & amount of sweat produced varies on extreme internal environmental conditions
  • sweat helps regulate body temperature
26
Q

Sensory receptors

A
  • enables body to detect changes in envrionment
  • nerve ending in skin is sense receptors
  • enables you to sense pain, pressure & temperature changes in external environment
  • thermorecptors detect temperature changes
27
Q

How does the body gain heat

A
  • heat is released within body as result of metabolic activities like cellular respiration
  • high levels of cellular respiration take place in muscles and liver. large amounts of heat is released in these organs and distributed to the rest of the body via bloodstream
  • can also gain heat through vigorous muscular activities, consumption of hot food and being in warm environments
28
Q

How does the body lose heat

A
  • through the skin
  • by evaporation of water in sweat at the surface of the skin
  • in faeces and urine
  • in the air that is exhaled
  • amount of blood flowing through skin capillaries affects heat loss through the skin surface
29
Q

What happens when body temperature rises above normal?

A
  • thermoreceptors in skin are stimulated. impulses are transmitted to the hypothalamus
  • arterioles in skin vasodilate, allowing more blood to flow through blood capillaries in skin, so more heat is lost through skin
  • sweat glands become more active and produces more sweat. as more water in sweat evaporates from surface of skin, more heat is lost from body
  • metabolic rate decreases, reducing amount of heat released
  • body temp decreases
  • body temp returns to normal
30
Q

What happens when body temperature drops below normal?

A
  • thermoreceptors in skin are stimulated. impulses are sent to hypothalamus
  • arterioles in skin vasoconstrict, allowing less blood to flow through blood capillaries in skin
  • sweat glands become less active and will secrete less sweat. since less sweat evaporate from surface of skin, less heat is lost from the body
  • metabolic rate increases and increases amount of heat
  • if above is not enough, shivering occurs, increasing amount of heat released

Biology 🦠 (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions