40 Basic Principles Flashcards
1
Q
What is is called when evolutionary animals have similar features and what does it suggest?
A
Convergent evolution, which shows that it is likely the most efficient form.
2
Q
What is an example of convergent evolution?
A
Penguins, Seals and Tuna are all aquatic animals that are fusiform (smooth and tapered at both ends)
3
Q
What circulation do hydras have?
A
Their body consist of a two cell thick tube. The cells on the outside are obviously in direct contact with the outside so don’t need circulation.
The inside of the tube is hollow and filled with water, known as a gastrovascular cavity so that all cells are in contact with the outside and thus circulation isn’t needed per se.
4
Q
Why are parasitic tapeworms so long?
A
This ensures they are thin so that each cell is close to the nutrient rich intestinal fluid.
5
Q
What is the advantage of having exchange systems i.e. alveoli inside the body as opposed to on the surface?
A
- Reduces dehydration
- Allows streamlined skin
- Protects them from damage
6
Q
What is the fluid between cell called?
A
Interstitial fluid.
7
Q
What are the main mammalian organ systems?
A
Digestive, Circulatory, Respiratory, Immune/Lymphatic, Excretory, Endocrine, Reproductive, Nervous, Integumentary, Skeletal, Muscular
8
Q
What is the integumentary system?
A
Skin and its derivatives (i.e. hair, claws and skin glands)
9
Q
What organ system is the spleen in?
A
Immune/Lymphatic
10
Q
Name an organ that is in multiple organ systems.
A
Pancreas (digestive and endocrine)
11
Q
What are the main animation tissue types?
A
Epithelial, Connective, Muscle and Nervous.
12
Q
What are the forms of epithelial tissue?
A
Cuboidal epithelium, simple columnar epithelium, simple squamous epithelium, stratified squamous epithelium and pseudo stratified columnar epithelium.
13
Q
What is the structure of cuboidal epithelium?
A
A ring of dice-shpaed cells to form a tube or bag.
14
Q
Where is cuboidal epithelium found?
A
Kidney tubules and the walls of the thyroid and salivary glands as these cells are specialised for excretion i.e. of salivary amylase.
15
Q
What is the structure of simple columnar epithelium?
A
Large brick shaped cells form a grid of columns
16
Q
Where is simple columnar epithelium found?
A
The lining of the intestines as these cells are optimum for secreting digestive juices and absorbing nutrients while also preventing leakage.
17
Q
What is the structure of simple squamous epithelium?
A
A single layer of platelike cells that appear like scales.
18
Q
Where is simple squamous epithelium found?
A
It is thin and leaky. Therefore it is found in the lining of capillaries and alveoli as it facilitates diffusion
19
Q
What is the structure of stratified squamous epithelium?
A
Many layers of spumous i.e. disk shaped cells.
20
Q
Where is stratified squamous epithelium found?
A
Surfaces that are often exposed to abrasion i.e. outer skin and mouth lining.
This is because it is able to regenerate quickly. This is because new cells form at the bottom to replace cells that are sloughed off at the top.
21
Q
What is the structure of pseudo-stratified columnar epithelium?
A
A single layer of cells columnar but they are of different heights. Thus there is some overlap and the cells are more wedge shaped.
22
Q
Where is pseudo-stratified columnar epithelium found?
A
In mucous membranes where it is covered by cilia that sweep the film of mucus along it.
23
Q
Generally speaking, how are the cells of epithelium connected and what property does this yield?
A
They are often tightly packed and bonded by tight junctions. Therefore they are strong and act as a barrier against pathogens and water loss (except simple squamous)
24
Q
What is the general structure of epithelium?
A
They are polar i.e. have different sides. The apical surface is the one that faces the lamina or outside and thus is the ‘active side’ whereas the ‘basal surface’ is not in contact with the fluid/air etc.
Below the basal surface is the basal lamina. This dense mat of extracellular matrix separates the epithelium from other tissues.
25
What are the forms of connective tissue?
Loose connective tissue, fibrous connective tissue, bone, adipose tissue, cartilage and blood (yep-blood)
26
What is the basic structure of connective tissue?
A web of fibres forming an extracellular matrix, consisting of a sparse population of cells.
The matrix includes fibroblast cells which secrete fibre proteins. Macrophages engulf foreign particles and cell debris.
27
What are the types of connective tissue fibres and what property do they provide?
Collagenous fibres provide strength and flexibility, reticular fibres join connective tissue to adjacent tissue and elastic fibres make tissue elastic.
(a combination of these fibres leads to mixed properties)
28
What is the most widespread connective tissue in vertebrates?
Loose connective tissue.
29
What is loose connective tissue?
Binds epithelia to underlying tissues and holds organs in place. It consists of a loose weave of all three fibres and tis found in the skin and throughout the body.
30
What is fibrous connective tissue?
Dense with collagenous fibres and thus used in tendons and ligaments.
31
How are bones joined to each other and muscle?
Tendons join bones to muscles and ligaments connect bones at joints.
32
What is the structure of bones?
Bone consists of repeating units called osteons. Each osteon has concentric layers of the min- eralized matrix, which are deposited around a central canal containing blood vessels and nerves.
33
How are bones formed?
Bone-forming cells called osteoblasts deposits a matrix of collagen. Calcium, magnesium and phosphates collect in this matrix to form a tough structure.
34
What is adipose tissue?
Specialised loose connective tissue that stores fats using adipose cells distributed through its matrix.
35
Why is adipose tissue important?
It pads and insulates the body and provides energy stores.
36
How are fats stored within an adipose cell?
In fat droplets that swell and shrivel depending on whether there is lots or little fat.
37
What is the structure of cartilage?
Collagenous fibres are embedded in a rubbery protein-carbohydrate complex called chondroitin sulfate.
38
How is cartilage formed?
Cells called chondrocytes secrete the collagen fibres and chondroitin sulfate to form the strong yet flexible structure.
39
Where is cartilage found?
Many vertebrate embryos have skeletons made of cartilage that later harden into bone. Cartilage remains in some places like the nose and as cushions between vertebrae.
Some animals like sharks have cartilage skeletons/
40
Why is blood considered connective tissue?
It has a liquid extracellular matrix-plasma that supports cells.
41
What is the technical term for red blood cell?
Erythrocyte
42
What are the types of muscle tissue?
Skeletal muscle, smooth muscle and cardiac muscle.
43
What is the structure of skeletal muscle?
Bundles of muscle fibres. The arrangement of sarcomeres along these fibres gives it a striated appearance.
The muscle fibres are actually long cells that formed from the fusion of many cells and thus have multiple nuclei.
44
How does smooth muscle differ visually from skeletal muscle?
It does not have striations.
45
What is skeletal muscle also known as?
Striated muscle.
46
What is the structure of smooth muscle?
Spindle shaped cells without a striated appearance.
47
Where is skeletal muscle found?
In voluntarily controlled regions i.e.on the skeleton.
48
Where is smooth muscle found?
The involuntarily controlled regions such as the walls of the digestive tract, bladder and arteries etc.
49
What is the structure of cardiac muscle?
It is striated like skeletal muscle and similar in its properties. It differs int hat its fibres are joined by 'intercalated disks' that allow signals to pass between fibres for coordinated contractions
50
What are the forms of nervous tissue?
Neurons and Glia.
51
What are the functions of glia?
Nourish, insulate and replenish neurons (and sometimes regulate them)
52
What are the basic methods of co-ordination between animal cells?
Chemical signalling and Electrical (nervous) signalling.
53
What are chemical messengers that travel throughout the body called?
Hormones/
54
What system releases hormones?
Endocrine
55
Which form of signalling is more targeted?
They are both targeted as only specific cells have the specific receptors for a particular hormone they need to respond to.
Nervous signalling is more targeted as it can be directed to specific motor units etc.
56
What is the endocrine system suited to because of its properties?
Co-ordinating gradual change such as development and metabolic functions. It is also good at regulating a co-ordinating a response from a diverse group of cells i.e. stress
Nerve cells are fast and brief and thus are good at causing rapid action in a specific region i.e. muscles.
57
What are the basic strategies/philosophies of organisms in responding to changing environmental conditions?
Regulator or Conformer.
58
How do regulator and conformer organism differ in their response to external condition?
Regulators maintain their internal environment as a constant.
Conformers adjust their internal environment to meet that of the environment.
59
How much do internal conditions fluctuate in conformers?
Not necessarily much - for example some fish conform to the reasonably constant salinity of the ocean.
60
What is an example of an organism that is a conformer to one condition and a regulator to another?
The fish Bass conforms to the temperature of the water but it regulates its blood salinity so that it is different from the freshwater it lives in.
61
Generally speaking, which organism are conformers?
Often aquatic animals, but not exclusively.
62
What refers to the maintenance of a steady state i.e. a regulator?
Homeostasis.
63
Generally speaking, how do organisms maintain homeostasis?
Using negative feedback.
64
Describe the negative feedback model of homeostasis.
A variable i.e. temperature has a _set point_ that is the "goal"
If the _sensor_ detects that the temperature is dropping this acts as a _stimulus_ that triggers a _response_ i.e. heating.
As the variable becomes closer to the _set point_ to magnitude of the _stimulus_ and thus _response_ decreases (negative feedback).
65
How does homeostasis relate to equilibrium?
It is a state of dynamic equilibrium in which it is generally balanced but fluctuates, with such fluctuations mitigated with responses.
66
What roles does positive feedback play in homeostasis?
None that are notable
67
What is an example of positive feedback?
During birth the baby's head against the uterus trigger contractions. These contractions increase the pressure and thus the intensity of successive contractions.
68
Are the set points fixed?
No, they can change in what is known "regulated change"
69
What conditions could lead to "regulated change"?
Long-term change i.e. hormone concentration after puberty, Long-term cyclic i.e. menstrual cycle or short term cyclic i.e. day-night
70
What is responsible for regulating the day-night cycle of metabolic activity?
Circadian rhythm
71
Does the circadian rhythm occur in plants?
Yes
72
What is an example of a variable and a chemical regulated by the circadian rhythm?
Body temperature drops during the night meanwhile Melatonin concentration peaks during night time.
73
What causes an increase in muscle size after exercise?
The muscle fibres become larger but no new one are formed (muscle cells don't divide)
74
Why is thermoregulation important?
Too high temperatures can denature enzymes whereas low temperatures decrease the rate at which they function and could also cause freezing.
75
What rule correlates temperature to enzymatic action?
As the temperature increases by 10ºC chemical reactions tend to double their rate.
76
What are the two types of thermoregulation?
Ectothermy and Endothermy
77
What are Ectothermy and Endothermy often called?
Endothermy: 'warm blooded'
Ectothermic: 'cold blooded'
78
What organisms are endothermic?
Birds, mammals, some reptiles, some fish and many insects.
79
What organisms are ectothermic?
Amphibians, lizards, snakes, turtles, many fish and most invertebrates.
80
How does thermoregulation strategy affect an organism's range?
Very few endothermic organism are found in polar regions due to the high energy needed.
In the tropics animals are largely endothermic as the increased activity this yields is advantageous.
81
Where do ectotherms and endotherms derive thermal energy?
Endotherms: metabolic activity
Ectotherms: environments
82
How would an endotherm that lives in the desert differ from one that lives in tundra?
The dessert animal would be adapted to lose heat whereas the tundra animal would be adapted to conserve heat energy.
83
What advantages are there of ectothermy?
The reduced energy costs mean less food must be sourced.
84
What type of organism (endo/ecto therm) is more tolerant to chaining internal temperature?
Ectotherms
85
Generally speaking, how do endotherms and ectotherms differ in the way they regulate temperature?
Endotherms regulate temperature with physiological response i.e. increasing metabolism
Ectotherms regulate temperate with mainly behavioural responses i.e. basking in the sone
86
What is an animal whose internal temperature varies called and what is one whose temperature does not called?
A 'poikilotherm' has a changing temperature whereas as 'homeotherm' has a relatively constant temperature.
87
Are all ectotherms poikilotherms and are all endotherms homeothermic?
No: Some ectotherms are homeothermic as they live in waters with a regular temperature.
Some endotherms are poikilothermic such as bats and hummingbirds that enter inactive states.
88
What are the basic mechanisms for maintaining a constant temperature?
Insulation, Circulatory adaptations, Evaporative cooling, Behaviour and Adjusting metabolic rate
89
What are some typical sources of insulation?
Feathers, fur and blubber
90
Can insulation be adjusted based on stimuli?
Yes, for example many mammals and birds react to cold temperatures by raising their fur/feathers. This traps more air and thus increases the insulation effect.
91
What coating applied to fur and feathers improves its insulation ability?
During preening birds add oil, as do many mammals, to their feathers/fur to make them more waterproof and thus better insulators.
92
What is an example of circulatory adaption to thermoregulation?
When it is cold "vasoconstriction" occurs in arteries that lead to the skin. This constriction reduces blood flow to and thus heat loss from the skin.
When it is hot the opposite: "vasodilation" occurs to maximise blood to the skin and thus heat loss.
93
What principle prevents excessive heat loss from the extremities?
Countercurrent exchange (see printed page)
94
What are some examples of maximising cooling by evaporative heat loss?
Sweating, panting and getting wet.
Some birds like pigeons have a pouch in their throat that is surrounded by blood vessels and can be fluttered to increase evaporation and thus heat loss.
95
What issue can evaporative heat loss bring?
Dehydration (especially since many hot regions are deserts)
96
What are some examples of behavioural response for thermoregulation?
Basking in the sun, hibernation and huddling.
Also many dessert animals are nocturnal.
97
What is an ability to adjust heat production for thermoregulation called?
Thermogenesis.
98
What is thermogenesis divided into?
Non-shivering thermogenesis and shivering.
99
How does shivering lead to thermogenesis?
Muscles are inefficient as are the processes that feed them (respiration etc.) and thus release heat.
100
What is non-shivering thermogenesis typically entail?
Increasing metabolic processes.
Some mammals have hormones that cause mitochondria to produce heat instead of ATP
101
What structure is specialised for non-shivering thermogenesis?
Brown fat which is found in the necks and between the shoulders of humans (especially infants) is specialised for thermogenesis.
102
What is an example of an animal that fluctuates between exothermic and endothermic?
Pythons are typically ectothermic but when they are incubating eggs they become endothermic through shivering.
103
How can acclimatisation occur in thermoregulation?
Many animals grow blubber and shed at specific times.
Animals can also produce many variants of enzymes that perform the same function but operate at different temperatures to promote thermoconforming.
The proportion of unsaturated to saturated lipids in membranes may change as unsaturated lipids keep membranes fluid at low temperatures.
Some Arctic fish produce 'antifreeze' to prevent ice crystals forming in their cells.
104
Where are the sensors of temperature?
In the hypothalamus which measures the temperature of blood from the ear.
105
Why do animals get fevers?
This is an intentional response that is regulated by the hypothalamus and seen in ectotherms like lizards that seek a warmer environment when infected with bacteria.
This suggests that it impairs the function of bacteria etc. or allows the immune cells to operate more effectively.
106
What are an animals energy requirements related to?
It's size, activity and its environment.
107
What does metabolic rate refer to?
The sum of all energy used in biochemical reactions in a given interval of time.
108
How can metabolic rate be calculated?
- heat emitted
- oxygen consume/ CO2 released
- over a long term: food consumed
109
What is minimum metabolic rate measured?
In endotherms it is called the basal metabolic rate (MBR) and is at a 'comfortable temperature' under no stress and without digestion
In ectotherms it is called 'standard metabolic rate' (SMR) and is at a specific temperature.
110
How does body size relate to metabolic rate?
The smaller the organism, the more energy is needed per gram of mass
111
How does body size mathematically relate to metabolic rate?
Metabolic rate is proportional to mass^(3/4)
112
How can energy be conserved?
Torpor, which is a physiological state of decreased activity.
113
Where is Torpor seen?
Many animals are sedentary after eating as they no longer need to be active
Hibernation, which is long term Torpor, is seen in many animals
114
What type of animal is associated with Torpor and why?
Small endotherms as they have higher relative energy costs when active and also require less food.
115
What happens to the circadian rhythm in hibernating animals?
It often stops completely or slows
116
In humans what regulates temperature?
The hypothalamus
117
What is miction?
Passing urine
118
What is piloerection?
Goosebumps
119
What is the technical term taste and what is an example of a structure bearing this name?
Gustation. For example "gustatory papillae" are tastebuds
120
Why do athletes typically have lower resting heart rates?
They tend to have higher systolic volumes i.e. blood pumped per contraction.
