Homeostasis Flashcards

1
Q

What is homeostasis?

A

the body’s self regulating ability to maintain internal stability due to adusting from internal and external conditions to help it survive

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2
Q

What is a stimulus?

A

A change in the external or internal environment

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3
Q

What is a receptor?

A

A receptor detects the stimulus and transfers this stimulus into a chemical or electrical signal for the modulator

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4
Q

What is a modulator

A

The modulator compares the information received by the receptor to the ideal condition the body aims to achieve/maintain, and will release molecules to go an alter the function of an effector to reach the ideal condition again.

A modulator is most commonly the brain, however it can also be a specific cell type

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5
Q

What three neurons make up the modulator?

A

sensory neuron
relay neuron
motor neuron

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6
Q

What is an effector

A

A molecule (hormone), cell or organ that responds to a signal from the modulator and produces a response

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7
Q

What is a response?

A

Any change in the function of a target cell, organ or organism after stimulation from an initial signal.

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8
Q

skip

A

.

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9
Q

What is a positive feedback system?

A

A positive feedback system occurs when the response increases/supports the initial stimulus, instead of trying to counteract it (rare in the body and do not form part of homeostasis), positive feedback systems are drawn with arrows creating a loop

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10
Q

what is an example of a positive feedback system

A

pregnancy
a baby takes up space in the uterus
stretch receptors detect the change in space, and how it has shrunk
the body then causes uterine muscles to contract, and the contractions continue to get stronger until the baby is delivered.

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11
Q

what is a negative feedback system

A

a negative feedback system occurs when the response counters the stimulus, meaning the response attempts to revert the system back to the state it was in before the stimulus occured

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12
Q

What is thermoregulation

A

the homeostatic process of maintaining a constant internal temperature, which occurs via negative feedback

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13
Q

what is the stimulus response model for when the core body temperature decreases?

A

Receptor: thermoreceptor
Modulator: hypothalamus
effector: Skeletal muscle cells
small blood vessels in the skin
cerebral cortex
arrector pili muscles
cells
brown fat

response ( in respect to the order of effector)
shivering
constriction of arterioles
change in behavior
lifting of the hair
increase in metabolic rate
burning of triglycerides

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14
Q

What is the stimulus response model for when the bodys core temperature increases:

A

receptor: thermoreceptors
modulator: hypothalamus
Effector: sweat glands
small blood vessels in the skin
cerebral cortex
arrector pili muscles
cells

Response (in respect to the order of the effector):
sweating
dilation of arterioles
change in behavior
flattening of hair
decrease in metabolic rate

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15
Q

What does the body do when its blood glucose levels decrease?

A

receptor: alpha cells
Modulator: secretes glucagon
Effector: liver cells
Response: glycogen breakdown

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16
Q

What does the body do when its blood glucose levels increase?

A

receptor: beta cells
Modulator: secrete insulin
Effector: liver cells
skeletal muscles

Response (in respect to effector order)
increased uptake of glucose
increased production of glycogen

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17
Q

Does oxygen diffuse via simple diffusion

A

yes

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18
Q

Can carbon dioxide diffuse easily through the membrane?

A

yes

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19
Q

Can sugars diffuse easily through the membrane?

A

no

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20
Q

can animo acids diffuse easily through the membrane?

A

no

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21
Q

What characteristics define asexual reproduction?

A
  • does not require the fusion of gametes
  • commonly occurs in unicellular and simple, multicellular organisms
  • only one parent is involves
  • Offspring are genetically identical4 to parents
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22
Q

What characteristics define sexual reputation?

A
  • involves the fusion of two haploid gametes, in a process known as fertilization
  • forms a single, genetically unique diploid zygote
    -each parent makes a genetic contribution to the offspring via DNA from their gametes
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23
Q

What are the strengths of sexual reproduction

A
  • increases genetic diversity of a population
  • Reduces the risk of birth defects and genetic diseases
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24
Q

what are the strengths of asexual repdocution

A
  • more frequent and energy efficient (uses less energy)
  • fine tuned to thrive in a steady environment, as offspring are clones
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25
Q

What are the weaknesses of sexual repdocution

A
  • more time-consuming and energetically expensive
26
Q

what are the weaknesses of asexual repdroduction

A

hinders genetic diversity

27
Q

What is meiosis?

A

A type of cell division where a cell divides twice to make 4 haploid cells (gametes)

28
Q

What happens in meiosis 1

A

the chromosomes in the homologous pair separate and are pulled to opposite poles of the cell

29
Q

what happens in meiosis 2?

A

the chromatids in the double chromosome are pulled apart forming a single chromosome, and the haploid gametes are produced

30
Q

what is crossing over?

A

the exchange of genes between homologous chromosomes, which results in a mixture of parental characteristics in offspring

31
Q

What are the four stages of somatic cell nuclear transfer

A
  • enucleation: The removal or destruction of the nucleus from a donated egg cell to produce an enucleated egg cell

-extraction: The donated somatic cells nucleus (cell of the animal wanted to be cloned) is extracted

-insertion: The somatic cells nucleus, is inserted into the enucleated egg cell

-development: following insertion, the cell can now divide and develop into an embryo, which is then implanted into a surrogate mother, and pregnancy continues are normal

32
Q

what is embryo splitting?

A

Ø After the successful fertilization of an egg cell, once it begins its formation as an embryo during the early stages it can be split, and each individual embryo will develop independently, meaning the offspring will be genetically identical.
Ø This process naturally occurs in the production of identical twins in humans, embryos can be artificially split for agricultural applications.
Ø These artificially split embryos are then implanted into surrogates, where they can develop independently.
Embryo splitting must occur when it only has between 6-8 cells, in which all cells are totipotent, and are capable of developing into viable embryos.

33
Q

what is osmoregulation?

A

Osmoregulation is the homeostatic regulation of osmolality in the body, via the alteration of water and solute balance.

34
Q

what does the body do when its water levels decrease?

A

receptor: baroreceptor
osmoreceptor

Modulator: Kidney cells release renin
Hypothalamus releases ADH

Effector: Increased sodium reabsorbtion
Greater presence of aquaporins
thirst centre stimulated

Response: Increased water consumption
Increased water reabsorbtion

35
Q

what does the body do when its water levels increase?

A

Receptor: Baroreceptor
osmoreceptor

Modulator: Hypothalamus suppresses the release of ADH

Effector: Decreased sodium reabsorbtion
Thirst center suppressed

Response: Decreased water consumption
Decreased water reabsorbtion

36
Q

What are the three types of adaptions

A

Behavioral- : Adaptions that are the actions or activities of an organism that enable it to survive in its environment.

Structural- Physical (external) features or parts of an animal or plant which help it survive in its environment

Physiological- Internal or cellular feature that helps an organism survive in its environment.

37
Q

What is a keystone species?

A

An organism that helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exist altogether.

38
Q

What is an apex predator

A

A predator that has no natural predators and is at the top of its food chain

39
Q

What is an ecosystem engineer?

A

An organism that creates, significantly alters or maintains the structure of an environment.

40
Q

What is symbiosis?

A

An interaction between two organisms of different species living in close proximity to each other.

41
Q

What is competiton?

A

Describes interactions between two or more organisms rivalling for the same pool of resources (food, mate, shelter etc). When two organisms compete for the same limited resource, the availability of the resource in the environment decreases

42
Q

What are the two types of competition

A

Interspecific competition: Competition between two individuals of a different species
Intraspecific competition: Competition between two individuals from the same species.

43
Q

What are the 6 types of relationships?

A

Mutualism (+/+)- both benefit
Commenalism (+/0)
Predatation (+/-) Involves one organism hunting and killing the other for food
Paratism (+/-) Interactions where an organism obtains nutrients at the expense of a host
Amensalism (0/-)
Competition (-/-)

44
Q

can cancer cells grow exponentially?

A

yes

45
Q

can cancer cells migrate to other parts of the body?

A

yes- only malignant however

46
Q

what is a stem cell?

A

an undifferentiated cell with the capacity of differentiating into specialized cells

47
Q

what are totipotent cells?

A

stem cells that can differentiate into any cell type
- zygote

48
Q

what are pluripotent cells?

A

can differentiate into multiple cell types

blasocyst

49
Q

what are multipotent cells?

A

can diffrentiate into a limited number if specialised cell types

  • bone marrow
    -umbilical cord
    -
50
Q

what are the four stages of apoptosis?

A

1 healthy cell
2 shrinkage
3 blebbing
4 apoptotic bodies
5 phagocytes digest the apoptotic bodies by phagocytosis

51
Q

what is the intrinsic pathway?

A

initiated by the detection of internal cellular damadge by mitochondria

52
Q

what is the extrinsic pathway?

A

initiated by the reception of extracellular death signalling molecules

53
Q

where is bile produced?

A

liver

54
Q

where is bile stored?

A

gall bladder

55
Q

where are digestive enzymes produced?

A

pancreas

56
Q

is the gall bladder, pancreas apart of the digestive tract

A

no they are accessory organs

57
Q

where is water reabsorbed in the nephron

A

loop of henle
collecting duct

58
Q

where are salts reabsorbed in the nephron

A

loop of henle

59
Q

where is glucose reabsorbed in the nephron

A

proximal convolnted tube

60
Q

is urea reabsorbed in the nephron

A

no