Body Balance Flashcards

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1
Q

What is homeostasis? (h)

A

Homeostasis is your body’s ability to regulate and maintain conditions inside your body, regardless of changes to external environment.

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2
Q

What are some conditions in the body that need to be kept consistent? (H)

A
  • Body temperature at 37’c
  • The amount of water inside our body
  • Blood sugar levels
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3
Q

How does the body maintain homeostasis? (H)

A

Negative feedback loops
It occurs to reduce/remove the original stimulus to maintain homeostasis.

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4
Q

Explain the role of the stimulus response model? (H)

A
  1. First we need receptors to detect changes (stimulus).
  2. We need a processing center (CNS) to receive information and coordinate our response.
  3. Finally we need effectors to produce the response.
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5
Q

Stimulus meaning (H)

A

Any detectable change in the environment

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6
Q

Receptor meaning (H)

A

A cell or group of cells that receive stimuli: sense organ.

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7
Q

Control centre meaning (H)

A

A place where a series of operations is directed.

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8
Q

Effector meaning (H)

A

A bodily part that becomes active in response to stimulation (such as muscles or glands)

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9
Q

Response meaning (H)

A

Response of the effector feeds back to reduce the effect of stimulus and returns variable to homeostatic level

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9
Q

What is a negative feedback loop?

A

Negative feedback is a response triggered by changed conditions and serves to reverse the change.

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10
Q

Explain how blood glucose levels are regulated (H)

A

Insulin (Low Blood Glucose): When blood glucose is high (after eating), the pancreas releases insulin. Insulin helps cells absorb glucose for energy and stores excess glucose in the liver as glycogen.

Glucagon (High Blood Glucose): When blood glucose is low (between meals or during fasting), the pancreas releases glucagon. Glucagon signals the liver to break down glycogen into glucose and release it into the bloodstream.

Homeostasis: This balance between insulin and glucagon keeps blood glucose levels stable, typically between 70-100 mg/dL.

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11
Q

What happens in diabetes. (H)

A

Type 1: The immune system mistakenly attacks and destroys insulin-producing beta cells in the pancreas. Pancreas produces little/no insulin, which is essential for helping cells absorb glucose from the blood. Without enough insulin, glucose builds up in the bloodstream (hyperglycemia) because cells can’t take it in for energy.

Type 2: The body becomes resistant to insulin, or the pancreas doesn’t produce enough insulin to maintain normal blood glucose levels. Insulin is less effective at helping glucose enter cells, so blood glucose levels rise.

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12
Q

What is a positive feedback loop (H)

A

A positive feedback loop is when response to a stimulus amplifies the original signal, rather than counteracting it. The output of the system enhances/accelerates the activity of the system, leading to a greater response.

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13
Q

What is the role of the endocrine system?

A

To maintain homeostasis (a stable internal environment) and to coordinate the body’s long-term activities by sending chemical signals throughout the body.

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14
Q

What is a hormone? How does it travel in the body?

A

A chemical messenger that is secreted from glands into the bloodstream and affects cells in another part of the body. They only work on cells called target cells.

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14
Q

Name 3 areas that the endocrine system regulates

A
  • Growth and development
  • Levels of salts and sugars in your blood
  • Appetite
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14
Q

What is an endocrine glad? What does is secrete?

A

An endocrine gland is a gland that secretes hormones into the bloodstream.

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14
Q

How do hormones ‘know’ which cells are their target cells

A

Target cells have receptors to ‘recognise’ the hormones and allow them to influence that cell to respond.

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15
Q

What controls the release of hormones? Give examples of different stimuli

A

External stimuli - via nerves from sensory organs in the nervous system eg. loud noise
Internal stimuli - via nerves and other hormones from inside your body eg. your sick and develop a fever

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16
Q

Why is the pituitary gland called the master gland?

A

It controls the functions of many of the other endocrine glands

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17
Q

Name an example of an endocrine disorder. What has gone wrong to produce these systems.

A

Diabetes, occurs when the pancreas does not produce enough insulin.

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18
Q

DNA

A

The blueprint of life and is in all living things, it stores the genetic material for an organism.

Deoxyribonucleic acid

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19
Q

Gene

A

Segment of DNA that codes for a protein and trait

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20
Q

Chromosomes

A

contains gene’s that determine the traits for the organism

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21
Q

Nucleus

A

A part of the cell containing DNA and RNA and responsible for growth and reproduction

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22
Q

Nucleotide

A

a compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.

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23
Q

What are chromosomes? where are they found in a cell?

A

Found in the nucleus they are DNA which has been tightly wounded into an x

23
Q

What are genes? What are they made of? what do they code for?

A

Segment of dna that codes for a specific trait

24
Q

Organism

A

A living thing

25
Q

What is the difference between a gene and a genome?

A

A genome is an organisms complete set of DNA, including all of its genes.

26
Q

What is the function of DNA? describe its structure. what hold the two strands together

A

DNA contains the instructions for making proteins which code for traits,
it is in a double helix shape
contains genes
held together by a hydrogen bond

27
Q

What is the nucleotide? Name the three components of a nucleotide?

A

A compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.

Consist of, nitrogen base deoxyribose sugar, and a phosphate group

28
Q

What is the base pairing rule?

A

A=T and G=C

29
Q

Complementary DNA strand

A

Strand of DNA that pairs with a template of the original DNA strand.

30
Q

What is the main function if RNA? Describe its structure.

A

To convert information stored in dna to proteins
1 strand/helix

31
Q

What are the similarities and differences between DNA and RNA?

A

Both contain nucleotides, however they have different bases

32
Q

What are proteins? What function do they have in a cell?

A

Proteins are made up of amino acids

They are required for structure, function and regulation of bodies tissue and organs

33
Q

What are the steps required to produce a protein from DNA?

A

Transcription and translation

Transcription - the DNA is copied into a molecule of RNA called messenger RNA by an enzyme of RNA polymase

Translation - the messenger RNA directs the production of a chain amino acids that form a protein

34
Q

What are the main phases of the cell cycle?

A

Interphase, mitosis, cytokinesis

35
Q

Interphase

A

Cell grows, copies its DNA and carries out normal functions, longest stage of the cell cycle, cells are not actively dividing they are said to be in interphase

36
Q

What is occurring mitosis

A

Mitosis - contents of the nucleus are divided into equal parts

P - prophase
M - metaphase
A - anaphase
T - telophase

37
Q

Cytokinesis

A

The final stage of the cell cycle, in which the cells cytoplasm divides, distributing organelles into each new cell.

37
Q

What phases are part of interphase. Explain

A

G1 - growth, cell makes protein and increases in size
S - genetic material is synthesised or replicated
G2 - cell continues to grow

38
Q

What proportion of the cell cycle is taken up by mitosis?

A

Mitosis takes up a small proportion of the entire cell cycle, typically around 10%.

39
Q

What are the differences between cytokinesis in animal and plant cells

A

In animal cells the cell pinches down the middle (cleavage furrow)
In plant cells a temporary cell plate grows and divides the cell into two

40
Q

How is the cell cycle regulated to deal with problems

A

Checkpoints in the cell cycle will prevent cell division if
- the cell is short of nutrients
- DNA in the nutrients has not been replicated
- DNA is damaged

41
Q

How do mutations result in a lack of control of the cell cycle?

A

The unregulated cell cycle can result in uncontrolled decision of cells leading to cancer

42
Q

DNA replication, When and why does this process occur in cells?

A

Occurs during the S phase of interphase, so that the daughter cell has the DNA

43
Q

Identify the role of helicase and DNA polymerase

A

Helicase - helicase breaks the hydrogen bonds which unzips the parent DNA
DNA polymerase - it joins adjacent nucleotides to form new sugar-phosphate backbones.

43
Q

Explain the semi conservative. Draw a diagram to explain this

A

Each new molecule now contains one parent strand and one daughter strand

43
Q

What is the name of the original strands of DNA
What is the name of the new strands of DNA

A

Parent strand
Daughter strand

44
Q

What is produced at the end of DNA replication

A

Two DNA molecules one is new and one is old

45
Q

Why do cells need to divide/reproduce

A

To replace dead, damaged or infected cells

46
Q

Know the names and main events occurring in each stage
prophase, metaphase, anaphase and telophase

A

Prophase - DNA coils tightly and becomes visible as chromosomes

Metaphase - chromosomes line up along the cells middle called centimetre

Anaphase - sister chromes seperate, pulled towards different sides

Telophase - separation of chromosomes is complete

47
Q

What is cytokinesis?

A

Division of the cytoplasm and organelles

48
Q

Describe the cells produced through mitosis

A

Two identical daughter cells, and have the same number of chromosomes as the parent

49
Q

What happens if a cell undergo too much or too little mitosis?

A

Mitosis is a bad thing when it is not needed, these cells can take over, they don’t function properly, they make copies without any control, and can result in cancer

50
Q

Pituitary gland

A

Master gland, produces growth hormones

51
Q

Adrenal gland

A

Hormones that deal with stress, releases adrenaline

52
Q

Thyroid gland

A

Regulates metabolism, hormones thyroxine

53
Q

Pancreas

A

Regulate blood sugar levels, releases insulin and glucagon

54
Q

Ovary

A

Reproductive development, releases oestrogen

54
Q

Testes

A

Reproductive development, releases testosterone

54
Q

Pineal gland

A

Controls sleep wake patterns, releases melatonin

55
Q

What is semi conservative?

A

Each new cell gets one old strand and one new strand.

56
Q

Example of a negative feedback loop (overheating)

A

Stimulus: Body temperature rises above the normal range (e.g., due to exercise or hot weather).

Receptor: Thermoreceptors in the skin and brain detect the increase in body temperature.

Control Center: The hypothalamus in the brain receives the information and activates mechanisms to cool the body down.

Effectors:
Sweat glands increase sweat production to cool the body through evaporation.
Blood vessels near the skin surface dilate (vasodilation), allowing more heat to escape.
Response: As the body cools, the temperature decreases, and the thermoreceptors detect this change.

Negative Feedback: Once the body temperature returns to normal, the hypothalamus reduces the signals to the sweat glands and blood vessels, stopping the cooling processes.

57
Q

Example of a positive feedback loop (Labor)

A

Stimulus: The baby’s head presses against the cervix during labor.

Receptor: Stretch receptors in the cervix detect the pressure and send signals to the brain.

Control Center: The brain (hypothalamus) releases the hormone oxytocin from the pituitary gland.

Effector: Oxytocin causes the muscles of the uterus to contract more strongly, which pushes the baby further down the birth canal.

Response: As the baby’s head presses harder on the cervix, the stretch receptors detect the increased pressure and signal for more oxytocin release, causing stronger contractions.

Amplification: The release of oxytocin increases uterine contractions, which pushes the baby further down, increasing pressure on the cervix, leading to more oxytocin release, and so on.

End of Loop: The cycle continues until the baby is delivered, at which point the cervix no longer stretches, the stimulus stops, and oxytocin release decreases, halting the loop.