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Biology 1/2 > HOMEOSTASIS > Flashcards

HOMEOSTASIS Flashcards

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1
Q

define tolerance range

A

The tolerance range is specific to species and is the range of environmental conditions that are tolerable for its survival. Too little or too much of a specific environmental condition may result in death.

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2
Q

define optimal range

A

Optimal range: is the climate conditions an organism thrives at

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3
Q

name different human body functions that are controlled by homeostasis and what is their normal tolerance range

A

temperature: 36.1-37.8 degrees Celsius
blood glucose: 3.6-6.8 mmol per L
water: daily intake must balance out the daily loss

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4
Q

neurons versus nerves

A
  • Nerves are individual nerve cells which are a collection of neurons and part of our nervous system
  • Neurons are information messengers. They use electrical impulses and chemical signals to transmit information between different areas of the brain and between the brain and the rest of the nervous system
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5
Q

Different types of neurons and their functions, also what are their other names

A
  • sensory (afferent) Sensory nerves carry information from the sense organs and other body receptors to the central nervous system for processing
  • motor (efferent): send information AWAY from the central nervous system to muscles or glands.
  • interneurons (relay): send information between sensory neurons and motor neurons. Most interneurons are located in the central nervous system.
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6
Q

what are the main parts of a neuron and what do they do

A
  • dendrites: receive signals from other cells
  • axon: transfers signals to other cells and organs
  • axon terminal: forms junctions with other cells
  • cell body: organises and keeps the cell functional
  • myelin sheath: increases the speed of the signal (a fatty layer)
  • Schwann cell: produces the myelin sheath (the little cells along the axon)
  • node of Ranvier: allows diffusion of ions (in between Schwann cells)
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7
Q

what is the CNS and what type of neurons and where are they found

A

Your central nervous system (CNS) is made up of your brain and your spinal cord, and is one of two parts of your nervous system
It consists of interneurons

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8
Q

what is the PNS and what type of neurons and where are they found

A

The peripheral nervous system (PNS) is the division of the nervous system containing all the nerves that lie outside of the central nervous system (CNS). The primary role of the PNS is to connect the CNS to the organs, limbs, and skin.
It consists of motor and sensory neurons

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9
Q

what is the endocrine system

A

The endocrine system is made up of glands that make hormones

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10
Q

what is the nervous system

A

The nervous system controls everything you do, including breathing, walking, thinking, and feeling. This system is made up of your brain, spinal cord, and all the nerves of your body.

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11
Q

compare the endocrine and the nervous system

  • its speed of message
  • its speed of response
  • its duration of response
  • its spread of response
  • how the message travels through the body
  • type of message
A

endocrine:

  • its speed of message: slow
  • its speed of response: slow
  • its duration of response: long lasting
  • its spread of response: usually widespread
  • how the message travels through the body: circulatory system - bloodstream
  • type of message: hormones (chemical)

nervous:

  • its speed of message: fast
  • its speed of response: immediate
  • its duration of response: short
  • its spread of response; localised
  • how the message travels through the body: in the nervous system - along nerves and across synapses
  • type of message: electrical impulses
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12
Q

what are synapses

A

Synapse; Synapse, also called neuronal junction, the site of transmission of electric nerve impulses between two nerve cells (neurons) or between a neuron and a gland or muscle cell (effector)

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13
Q

what are hormones

A

Are chemical messengers that are produced by endocrine glands
Transported around the body via the circulatory system

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14
Q

what important hormones do the pituitary gland and pancreas produce and where are they located

A

pituitary: located in the brain and produces ADH
pancreas: located between kidneys and produces insulin and glucagon

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15
Q

what is Specificity

A

Hormones will only affect/activate their target cells.
“Lock and Key” hormone must “fit” receptor to activate it.
Receptors can be located on the cell membrane or inside the cell.
A hormone binding to the receptor activates signal transduction, a series of chemical reactions (domino effect) ending with a change, (gene expression, enzyme activity).

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16
Q

what are Negative feedback loops

A

All homeostatic mechanisms use negative feedback to maintain a constant value (called the setpoint).
Negative feedback means that whenever a change occurs in a system, this automatically causes a corrective mechanism to start, which reverses the original change and brings the system back towards the setpoint (i.e. ‘normal’).
(operates in the opposite direction of the stimulus)

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17
Q

what are Positive feedback loops

A

Negative feedback is a regulatory mechanism in which the system responds in the opposite direction to the stimulus, maintaining a relatively steady value for body variables (homeostasis).
e.g. temperature, blood glucose levels.
Positive feedback is when the response to the stimulus is in the same direction as the stimulus. e.g. the onset of contractions during childbirth.

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18
Q

what happens in a normal reflex arc

A

stimulus (heat) -> receptor (thermreceptors) -> sensory neuron -> CNS (spinal cord) -> interneuron -> CNS -> motor neuron -> effector (bicep) -> response (pulling away)

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19
Q

what are the different receptors

A

Chemicals (chemoreceptors)
Temperature (thermoreceptors)
Pressure (mechanoreceptors)
Light (photoreceptors)

20
Q

what is thermoregulation

A

Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries

21
Q

what are the adaptations of being too hot

A

vasodilation: arteries dilate to release more heat
sweating
pilorelaxation: hairs flatten to stop trapping air/heat
stretching out: larger surface area

22
Q

what are the adaptations of being too cold

A

vasoconstriction: arteries get smaller to reduce blood going to the skin
shivering
piloerection: hairs raise to capture air/heat
curling up

23
Q

what are endotherms

A

are animals that produce their own heat.

24
Q

what are ectotherms

A

are animals that gain heat through the environment

25
Q

what are homeotherms

A

are animals that have a constant body temperature.

26
Q

what are Poikilotherms

A

are animals whose body temperature adjusts depending on the environment.

27
Q

Why is it so important for us to maintain our body temperature?

A

Human enzymes work best at 37ºC, so the body’s temperature is controlled

28
Q

what is osmoregulation

A

Osmoregulation is the regulation of an organism’s water content.
It keeps the organism’s fluids from becoming too diluted or too concentrated

29
Q

what is Osmosis

A

the diffusion of fluid through a semipermeable membrane from a solution with a low solute concentration to a solution with a higher solute concentration.

30
Q

what If the concentration of solutes is not equal on both side

A

there will be net movement of water molecules into or out of the cell, depending on whether the cell’s environment is isotonic, hypotonic, or hypertonic.

31
Q

what is tonicity

A

if the concentration of solutes ( the substance that dissolves in a solvent to produce a homogeneous mixture.) is not equal on both sides, there will be movement of water into or out od the cell, depending whether the cells environment is isotonic, hypotonic, or hypertonic

32
Q

what is hypertonic

A
  • lots of solute in the solution

- water moves out of the cells and cells shrink

33
Q

what is isotonic

A
  • equal concentration

- balanced

34
Q

what is hypotonic

A
  • less solute than in the cell

- cells take on water and burst (animal cells

35
Q

what is antidiuretic

A

helps to control fluid balance in an animals body by reducing urination, opposing diuresis. Its effects are opposite to a diuretic

36
Q

what is diuretic

A

promotes diuresis (increased urine production)

37
Q

what is ADH

A

Antidiuretic hormone is released by the pituitary at the base of the brain after being made in the hypothalamus. ADH has antidiuretic action that prevents the production of dilute urine

38
Q

what is the response to hypertonicity

A

decrease in water level and therefore solute concentration in the body is higher -> osmoreceptors in the hypothalamus (detects water concentration detects this change -> hypothalamus releases ADH and signals from thirst centre and released -> kidney tubules (process water in kidneys) become more permeable to water & thirst behaviour -> results in increased water absorption from kidney tubules, decreased urine volume and water intake

39
Q

what is the response to hypotonicity

A

increases in water levels and therefore decrease in solute levels in the body -> osmoreceptors in the hypothalamus detect this change -> hypothalamus sends signals to stop the release of ADH -> kidney tubules become less permeable to water -> decreased water absorption and increase urine volume

40
Q

what do the kidneys do

A

The kidneys remove urea and other toxic wastes from the blood, forming a dilute solution called urine in the process.

41
Q

what are the different tubes/veins leading in and out of the kidneys

A
  • The renal artery carries blood to the kidney
  • the renal vein carries blood, now with far lower concentrations of urea and mineral ions, away from the kidney.
  • The urine formed passes down the ureter to the bladder.
42
Q

what is the nephron

A

The important part of the kidney is a folded tube called a nephron. There are a million nephrons in each kidney. There are five steps in producing urine in a nephron:

43
Q

what is the loop of Henle

A

Loop of Henle – Formation of a Salt Bath. Most of the liquid is absorbed here - to recover water and salt from urine. it has a bigger surface area so it can absorb more water

44
Q

what are some of te adaptations of water loss

A 
structural:
Fewer stomata
Small leaves
Needle-like foliage
Thicker cuticles
Thick fleshy leaves that can store water
Loop of Henle longer in desert dwelling animals
physiological:
Reabsorb water
Produce highly concentrated urine
Rely on metabolic water
Osmoconformers
Osmoregulators

behavioural:
Spend most time in burrows
Absorb water from atmosphere
Drink water

45
Q

how are reflex arcs fast and why

A

they are fast because it helps keep the organisms from danger.
It is fast as it doesn’t go straight to the brain it just goes through the spinal cord so the interneurons can activate the motor neurons but the information goes to the brain later

Biology 1/2 (5 decks)

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