Communication and homeostasis Flashcards

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1
Q

Endocrine gland?

A

A gland that secretes its products directly into the bloodstream (travels further distances)

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2
Q

Homeostasis?

A

The maintenance of a condition of equilibrium or of near-constant internal conditions

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3
Q

Receptor?

A

A structure in the body that can detect changes in its environment and react to stimuli

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4
Q

Effector?

A

A structure in the body that responds to a stimulus and brings about a response (e.g muscles/glands)

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5
Q

Paracrine signalling?

A

Occurs between cells that are close together

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6
Q

Endocrine signalling?

A

Involves signalling over long distances, with the cell signalling molecule transported in the circulatory system

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7
Q

Oestrogen?

A

A female sex hormone (although also present in small quantities in males) that inna steroid and plays a role in the female reproductive cycle and the development of female secondary sex characteristics

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8
Q

Synapse?

A

A junction between two nerve cells, consisting of a minute gap across which impulses pass either by an electrical current (electrical synapse) or, more often, by diffusion of a chemical neurotransmitter (chemical synapse)

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9
Q

Negative feedback?

A

Type of control mechanism in which a change from the normal value of a physiological factor is detected and a response is made that restores the value to the norm

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10
Q

Thermal regulation?

A

The control of temperature

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11
Q

Endotherm?

A

An animal that maintains its body temperature using heat generated within its body tissues

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12
Q

Ectotherm?

A

An animal that absorbs heat from its environment to help regulate its body temperature

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13
Q

Radiation?

A

Is the loss of heat (in electromagnetic radiation form) from hot objects into cooler surroundings -main body heat loss

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14
Q

Convection?

A

The movement of currents/warm air upwards, because the density of air decreases when it is warm

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15
Q

Conduction?

A

Transfer of heat energy from a warmer material to a cooler one. The body can lose heat energy to the air by conduction, but because air is a good insulator, if a layer of air can be trapped around the body it will reduce further heat loss by radiation.

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16
Q

Evaporation?

A

Water evaporates from the skin which cools the surface, this is because heat energy from the skin is used to change water to water vapour (this is what happens during sweating)

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17
Q

Specific heat capacity?

A

The energy needed to change the temperature of 1kg of a substance by 1 Degrees Celsius

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18
Q

What is vasodilation (of skin capillaries)?

A

Muscles in arterioles near skin relax, increasing the volume of blood that can flow through them and therefore the capillaries, heat loss is maximised

19
Q

What does flattening of hairs do?

A

The hair erector muscles in skin relax in warm conditions to thin the insulating layer of air on the skin - more heat is lost

20
Q

What does erection of hairs do?

A

The erector muscles contract so that the hair stand up on end and a thick layer of air is trapped, insulating the body and reducing heat loss

21
Q

Basal metabolic rate?

A

The energy used by the body at rest to sustain its vital organs

22
Q

What does boosting metabolic rate do?

A

In cold conditions a hormone thyroxine is released from the thyroid gland just infant of the larynx, which boosts the basal metabolic rate, increasing heat production (as most chemical reactions in body are exothermic)

23
Q

What does shivering do?

A

It is a reflex action in response to a small drop in core body temp, a nervous mechanism. The effectors (muscles) rapidly and regularly contract which is the shivering and this generates heat which warms the blood (the heat is generated due to the metabolic reactions going on in the muscle)

24
Q

What does vasoconstriction do?

A

Arterioles contract/constrict near skin, so that the volume of blood through arterioles is decreased, so little blood reaches capillaries near the skin surface

25
Q

Where does blood go when arterioles go through vasoconstriction?

A

Blood is diverted to shunt vessels, deeper in the skin and do not lose heat to surroundings - reducing cooling of blood

26
Q

What are peripheral receptors?

A

Thermoreceptors found in the skin/mucous membrane - receptors for cold and heat. communicate with the hypothalamus

27
Q

How might endotherms also have homeostatic behavioural responses?

A

For example, if an animal lives in a hot climate they might spend all day in water to keep cool, or a group of cold penguins huddle together for warmth

28
Q

Autonomic nervous system?

A

The part of the nervous system that controls automatic responses, consisting of the sympathetic and parasympathetic nervous systems

29
Q

Parasympathetic nervous systems?

A

Rest and digest, slow down heart rate, breakdown food, slow down heart rate

30
Q

Sympathetic nervous system?

A

Activates fight of flight, increases heart rate

31
Q

What is the hypothalamus?

A

The centre for temp control, located in the brain - monitors core blood temp as blood passes through. It contains temp receptors and two control centres

32
Q

What are the two control centres in the hypothalamus called?

A

Heat loss centre and heat gain centre - they send out both nervous and hormonal signals which bring about various actions related to temp control

33
Q

What are the following processes controlled by, sweating/shivering/vasoconstriction/vasodialtion?

A

Nerve impulses via the autonomic nervous system

34
Q

What two communication systems do animals have?

A

The nervous system and the endocrine system

35
Q

What does the nervous system do?

A

Transmit electrical impulses

36
Q

What does the endocrine system do?

A

Produce hormones

37
Q

Which responses are slower?

A

Hormone responses are slower but longer lasting

38
Q

What things must be kept at constant levels in the body?

A

Temperature, water and CO2

39
Q

Core body temperature?

A

37 degrees Celsius

40
Q

How can body heat be gained?

A

Through respiration, shivering, exercise

41
Q

How can body heat be conserved?

A

Decreasing sweating, raising of hairs/feathers, reducing blood flow near the skin surface

42
Q

What are the two cell signalling pathways called?

A

The paracrine and endocrine signalling pathways

43
Q

How have multicellular organisms evolved?

A

Specialised cells/tissues have developed which carry out individual functions, but can work together in organs to carry out functions together - relating to the entire body

44
Q

What are cell signalling molecules?

A

Molecules that communicate with other cells/molecules in other areas of the body