Study- Term 3 Flashcards

1
Q

Homeostasis

A

Maintenance of a constant internal environment within a living organism despite internal or external changes to their environment

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

Stimulus

A

A detectable change in either the internal or external environment that acts as a signal for cells

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

Receptors

A

A specialised cell or group of specialised cells (sense organ) that receive stimuli

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

Regulator

A

A coordinating centre which the receptor sends a chemical message to that determines if a change is required

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

Effectors

A

Either a muscle (movement response) or gland (secretes molecules)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Response

A

The change in chemicals within a cell or within an effector organ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Chemoreceptors

A

Chemical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Photoreceptors

A

Light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Mechanoreceptor

A

Touch, pressure, stretching, motion, sound waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Thermoreceptor

A

Temperature, heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Nocireceptor

A

Potentially damaging stimuli or to actual damage

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

Feedback

A

The return of information

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Negative

A

An action that opposes the input

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Positive feedback

A

Instead of getting a counteracting response to some variable you instead intensify the variable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Negative feedback

A

When some variable triggers a counteracting response in order to come back to some set point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Hormonal homeostatic pathways

A
  • involve the endocrine system
  • can be slow
  • chemical message,travelling in bloodstream
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Neural homeostatic pathways

A

Involve nervous system
Very rapid
Electric impulse, travelling along nerves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Hormones

A

Chemical messengers that regulate the activity of cells and organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Endocrine

A

Travel long distances through the body to target cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Endocrine + hormones

A

Hormones produced in endocrine glands which are released directly into the blood vessels, work together to maintain homeostasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How hormones work

A

Hormones affect only certain tissue cells or organs called target cells or target organs
Target cells must have protein receptors present on the cell membrane to allow the hormone to attach
Hormones must bind to the target cell to influence the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Nervous system

A

Comprised of nerves (neurone)
Two parts:
-central nervous system (CNS)
-peripheral nervous system (PNS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Nervous system

A
  1. Receptor detects a change (stimulus)
  2. Receptor to the CNS by a sensory neurone
  3. CNS to an organ that carries out a response a motoneuron carries this message
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Motor neurone

A

Carry message from the brain to allow us to move our muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Inter neuron
Connect neurons to other neurons
26
Sensory neuron
Receive information from sense organs. Send sensory information to our brain and spinal cord
27
Thermoregulation
Maintenance of a constant internal temperature of an organism independent of the temperature of the environment
28
Endotherms
Most of their heat is generated internally through metabolic activity and they are not so reliant on environmental conditions
29
Ectotherms
Gets their body heat mainly from their environment and can tolerate a reasonably wide range of body temperatures
30
Thermoregulatory mechanisms: | Physiological mechanisms-
``` Evaporate heat loss Vasodilation Vasoconstriction Countercurrent Thermogenesis ```
31
Evaporate heat loss
Humidity affects thermoregulation by limiting sweat evaporation
32
Vasodilation
Dilation of blood vessels in the skin
33
Vasoconstriction
Constriction if blood vessels in skin
34
Countercurrent
Blood vessels in which heat flows warmer to cooler blood
35
Thermogenesis
Production of heat within tissues to raise body temp
36
Structural features- | Brown adipose tissue=
Specialised for rapid heat production, transfers food from energy to heat
37
Structural features: | Increase no. of mitochondria per cells=
Enables organisms to generate heat by increasing the rate at which they metabolise fats and sugars
38
Structural features: | Insulation-
Traps warm air to insulate organism
39
Behavioural responses: | Kleptothermy=
Sharing another organisms body heat
40
Behavioural responses: | Torpor=
Physiological state in which the metabolic rate is lowered to save energy
41
Behavioural responses: | Hibernation-
State of animal dormancy taking place in the winter
42
Behavioural responses: | Aestivation=
State of animal dormancy taking place in the summer
43
Homeostatic mechanisms: | Thyroid hormones-
Increase available energy in the body, as well as by increasing appetite pulse, the amount of oxygen delivered to different body parts and fat building up
44
Homeostatic mechanisms: | Insulin-
Promotes an increase in heat production and or vasoconstriction
45
Osmoregulation
The maintenance of a constant solute and water balance
46
Excretion
Removal of metabolic waste
47
Osmoconformers
Maintain internal environment that is isotonic (the same) to external environments
48
Osmoregulators
Actively control the levels of internal salt concentrations so that overall solute concentration is constant
49
Terrestrial animals
Must take in water to replace that which is continually lost in the process of eliminating waste and by evaporation from the lungs and body surface
50
Hormonal control of water balance in mammals
Antidiuretic hormone (ADH) is most important for controlling reabsorption of water—> released by pituitary glands
51
Vacuoles
- Store water and other substances in cells | - Important for plants as they help maintain turgor pressure against the cell wall when water levels are low
52
Waxy cuiticle
- waterproof layer covering leaf surface (epidermis) | - prevent water losses
53
Stomata
- found on leaf surface (epidermis) - surrounded by guard cells —>control opening and closing stomata - close when water levels in plant are low—> reduces water loss
54
Guard cells
- Cell walls are thicker next to stomata pore than next to surrounding cells -when they are full of water—>thin walls stretch more than thick ones —>two cells curve away from each other->opens stomata - when they lose water —> turgor pressure decreases —> cell walls become straighter—> stomata close
55
Diseases and it’s causes
Disease is a physiological abnormality or significant disruption in the health of an individual. It is caused by a variety of factors such as genetic predisposition, environmental conditions, poor nutrients and by pathogens
56
Infectious
They are caused by another organism or organic agent and can be passed from one individual to another either directly or indirectly. Are caused by pathogens which are biological agents that caused diseases or illnesses to a host
57
Non-infectious
They cannot be spread from one side of individual to another
58
Cellular vs non-cellular
Cellular=can reduce | non-cellular=cannot reproduce alone requires host
59
Virulence
Virulence of a pathogen refers to its ability to cause disease in a host
60
Pathogenesis
Pathogenesis refers to the mechanisms which have a lead to its current state
61
Virulence factors
Are molecules or strategies that can contribute to the survival of pathogen. they are typically proteins and include adherence factors, invasion factors, capsules, toxins, lifestyle changes
62
Adherence factors
Before a pathogen can cause a disease it must first enter the host for this to occur the pathogen must adhere to a molecule on the membrane of the host cell a starting point for the micro organism to penetrate tissues and colonise the host
63
Invasion factors
Are proteins that allow pathogens to enter cells. Produce proteins that either disrupt host cell membranes or stimulate Endocytosis into the host cells so the pathogens can get inside
64
Capsules
Bacterial capsule is a very large structure of many bacteria it is a polysaccharide layer that lies outside the outer membrane of the cell. It allows movement into the host cell easier
65
Toxins
Proteins that poison host cells and cause tissue damage.
66
Endotoxins
Bound to the pathogen and can induce inflammatory responses when the host tries to destroy it
67
Exotoxins
Are produced and secreted by pathogen once inside the host
68
Mode of transmission
Direct contact or indirect contact
69
Innate immune system
Non-specific defence mechanism that comes into play immediately or within hours of an antigens appearance in the body
70
Innate immune system includes
Physical barriers to prevent entry of pathogen and chemicals in blood, immune system cells that attack pathogens
71
First line of defence
Physical and chemical barriers prevent entry of pathogens