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Biology 1 > Module 4 B > Flashcards

Module 4 B Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Give 2 examples of cell specialisation in the human body

A

endothelial cells - form walls of blood vessels
muscle cells - cause peristaltic contractions

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2
Q

Key stages of animal embryogenesis

A

egg (cleavage - series of rapid cell divisions) –> bastula (gastrulation - cells move inwards to generate the germ layers) –> gastrula (organogenesis - formation of the tissues & organs of the body - neurulation) –> tail-bud stage –> differentiation commences & electrically active neural cells / muscles arise

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3
Q

Gastrulation & establishment of the germ layers

A
  1. Bastula (flattening)
  2. Cells at the base of the bastula begin to change shape
  3. Inward bulge formed by cells changing shape. Cells separate from outer layer & move inwards - form the mesoderm.
  4. Cells in the invagination form the endoderm layer.
  5. Endodermal cells extend, flatten, & undergo rearrangement to form a long thin tube - the gut
  6. Gastrula is formed. Future sites for the mouth & anus determined

blastopore = future site for anus

different types of tissue arise from the germ layers
- endoderm, mesoderm, ectoderm

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4
Q

Ectoderm

A

gives rise to external surfaces (e.g. skin) & the nervous system

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5
Q

Mesoderm

A

gives rise to many internal tissues like muscles, blood vessels, & other connective tissues

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6
Q

Endoderm

A

gives rise to the cells that line the alimentary canal & the various organs that branch off from it such as the lung, pancreas, & liver

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7
Q

Triploblastic animals

A

animals with 3 germ layers are called triploblast (most animals)

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8
Q

Diploblastic animals

A

animals lacking a mesoderm have 2 germ layers & include cnidarians like jellyfish & hydra (only have endoderm & ectoderm)

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9
Q

A stem cell division produces. . .

A

a new stem cell and a daughter cell that
can subsequently differentiate into other cell types

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10
Q

Organogenesis

A

involves several morphogenic processes - cell movement, cell adhesion, changes in cell shape
– interactions B/W the germ layers

Organogenesis is the process of formation of organs from three germ layers

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11
Q

Cell potency

A

ability of cell to give rise to other cell types

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12
Q

Describe epithelial tissue

A

2-D sheets of cells that cover the body surface internal cavities, & internal tubes such as the alimentary canal

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13
Q

Function of epithelial tissue

A

provide a barrier function b/w the body & outside world & b/w compartments of the body

endothelia –> epithelial tissues that line blood vessels & are of mesodermal origin

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14
Q

Epithelial cell features

A

apico-basally polarized

cell-cell junctions
tight junctions
– prevent passage of
small molecules between cells
* adherens junctions and
desmosomes provide mechanical
support
* Gap junctions allow cell cell
communication

cell-matrix junctions
attach epithelial cells to the
underlying extracellular matrix
(ECM) (called the basal lamina)

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15
Q

Functions of epithelia

A

glands – secretion of hormones, enzymes, sweat

intestine – absorption of nutrients

skin – protection from mechanical damage, heat loss, microbes, & water loss

airways – beating of cilia to keep airways clear of mucus & dirt

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16
Q

Connective tissue

A

support & connect other tissues
- usually consist of a few cells that exist in & contribute to an EXTRA-CELLULAR MATRIC (ECM)

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17
Q

ECM

A
  • an interlocking mesh of fibrous proteins within some ground material, usually liquid but solid in the case of bone
  • embedded proteins like collagen & elastin are secreted by cells, often by the cells within the matrix
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18
Q

Examples of connective tissue functions

A

tendons – strong connection b/w muscles & bones

bone – rigid support & protection of delicate tissues

adipose – storage & metabolism of fats

blood – transport of oxygen & carbon dioxide, nutrients, immune cells

cartilage – rubbery / flexible; shock-absorbing; friction reducing

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19
Q

Nervous tissue

A
  • processing info
  • gather info about the external & internal env.
  • control physiology & behaviour of body

NEUTRONS TRANSMIT ELECTRICAL SIGNALS CALLED ACTION POTENTIALS

GLIAL CELLS PROVIDE MECHANICAL & NUTRITIONAL SUPPORT FOR NEURONS
- do NOT generate action potentials (e.g. Schwann cell)

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20
Q

3 types of neurons

A
  1. sensory neurons
  2. interneurons
  3. motorneurons
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21
Q

sensory neurons

A

generate electrical signals based on dif. stimuli (e.g. touch receptors) – output to neurons

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22
Q

interneurons

A

take input from neurons - output to other neurons

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23
Q

motorneurons

A

take input from neurons - output to muscles

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24
Q

examples of sensory neurons

A
  • pressure receptors in skin
  • stretch receptors in muscle
  • olfactory receptors in nose
  • photoreceptors in eye
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25
Q

Muscular tissue (3 types) – generating contractile force

A
  1. skeletal
  2. cardiac
  3. smooth
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26
Q

skeletal muscle

A

connects to the skeleton & generates voluntary movements of the body

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27
Q

cardiac muscle

A

contraction of the heart under involuntary control

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28
Q

what causes muscle contraction?

A

caused by an ATP-dependent motor protein comprised of myosin filaments pulling on actin filaments - contraction is activated by electrical signals

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29
Q

smooth muscle

A

surrounds internal organs - mainly under involuntary control

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30
Q

Integumentary system

A

provides a barrier to outside environment (skin)

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31
Q

Respiratory system

A

gaseous exchange

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32
Q

gastrointestinal system

A

digestion of food, absorption of nutrients, & removal of waste

33
Q

urinary system

A

elimination of waste, regulating blood volume & pressure

34
Q

lymphatic system

A

controlling bodily fluids & movement of immune cells

35
Q

reproductive system

A

involved in propagation

36
Q

skeletal system

A

provides support for the body

37
Q

muscular system

A

enables locomotion & other bodily movements

38
Q

nervous system

A

control & coordination of various bodily activities & responses to the env.

39
Q

endocrine system

A

secretes hormones that regulate metabolism, growth, & development

40
Q

cardiovascular system

A

movement of blood around body

41
Q

Example of organ systems working together

A

Endocrine system: secretes hormones into blood
Digestive system: pass nutrients & water into blood & hormones
Respiratory system: oxygenates blood & removes CO2
Urinary system: removes nitrogenous waste from blood

42
Q

Stimulus-response model

A
  • receptor detects a change AWAY from the desired equilibrium value & signals to a control centre
  • control centre receives & processes this info & communicates to an effector
  • an effector creates a response that opposes the effect of the stimulus

–> negative feedback

43
Q

How do cells communicate with other cells?

A
  1. cytoplasmic connections (e.g. gap junctions in animals, plasmodesmata in plants)
  2. local signalling –> autocrine; juxtacrine; paracrine
  3. hormones in blood have long-distance, systemic effects
  4. in animals, cells can generate electrical signals (action potentials)
44
Q

3 main groups of animal hormones

A
  • steroid hormones (testosterone)
  • amine hormones (epinephrine)
  • protein hormones (insulin)
45
Q

Hydrophilic hormones

A
  • secreted from cell via exocytosis
  • binds to cell-surface membrane receptors
46
Q

lipophilic hormones

A
  • diffuses through membrane
  • binds hydrophilic transport proteins
47
Q

lipophilic

A

tending to combine with or dissolve in lipids or fats.

48
Q

consequences of low blood sugar (hypoglycemia)

A

seizures
loss of consciousness

49
Q

consequences of high blood sugar levels (hyperglycemia)

A

damages cells, causing heart disease, stroke, kidney disease, vision impairment

50
Q

Insulin causes liver cells to store glucose as glycogen

A

liver cells express the insulin receptor
insulin binding activates the receptor which has 2 effects:
1. Increases number of glucose transporters in
the membrane (yellow)
2. Activates an enzyme (glycogen synthase) that
converts glucose to glycogen
so blood glucose goes down

51
Q

glucagon causes glucose to be released

A

Liver cells also express the Glucagon G-
protein coupled receptor. Glucagon activating
its receptor has two effects:
1. Activation of glycogen phosphorylase
2. Inactivation of glycogen
This leads to breakdown of glycagon into
glucose molecules
glucose levels go up

52
Q

functions of plant hormones

A

growth & development
seed dormancy
defense against herbivores
stress response

53
Q

Which plant hormones promote stem growth?

A

auxin, brassinosteroids, & gibberellins
Abscisic acid promotes seed dormancy,
gibberellins promote seed germination

54
Q

How do auxin & gibberellin act?

A
  1. In the absence of the hormone, cellular responses are kept inactive by a repressor
  2. The hormone binds to a receptor, allowing the complex to enter the nucleus
  3. The complex binds to the repressor, stimulating the addition of a protein degradation signal
  4. The repressor is degraded, triggering a cellular response to the hormone
55
Q

under dry conditions in plants. . .

A

Abscisic acid (ABA) produced in roots and leaves
ABA causes guard cells to become flaccid and stomata close
guard cells have high water potential & low turgor pressure - water stress

56
Q

How does ACA stimulate a drought response?

A

prolonged ABA exposure activates a signalling pathway - triggers expression of genes that mitigate water stress
- increased root growth
- reduced shoot growth
- expression of proteins that stabilize cellular content

57
Q

What is the Ferguson reflex?

A

is a positive feedback loop that ensures that, once contractions begin, they build in strength
until the baby is delivered.

58
Q

How does ferguson reflex work?

A
  • pituitary gland stimulated to release oxytocin
  • oxytocin causes uterus to contract
  • baby pushing against cervix activates stretch receptor neurons
  • sensory neurons send signal to the brain (hypothalamus)
59
Q

Why do some animals lack a circulatory system?

A

bc their cells are all a short distance from the env - (e.g. animal is small, flat, hollow, porous etc)

60
Q

Animal circulatory system needed for:

A
  • transportation of substances
  • transportation of heat
  • transmission of force
61
Q

Animal circulatory systems need what?

A
  • a muscular pump
  • a circulating fluid
  • a system of tubular vessels that form a circuit
62
Q

Distinguish between open circulatory system & closed circulatory system

A

Open circulatory system: circulating fluid empties OUT into the body cavity
Fluid in circulatory system is SAME as that in body cavity (hemolymph)

Closed circulatory system: circulating fluid is contained within a network of vessels
Circulatory fluid is separate from interstitial fluid
Circulatory fluid is called blood plasma

63
Q

e.g. of animals w/ open systems

A

arthropods (insects, crustaceans, e.g. lobster, most molluscs)

64
Q

e.g. of animals w/ closed systems

A

worms, vertebrates (fish, birds, etc.) → have high metabolic activity

65
Q

Advantages of closed circulatory system:

A
  • Fluid flow is MORE rapid in closed system – faster metabolism
  • Control of flow – direct flow to where it is needed
  • Specialized content of blood plasma – retained cells / large molecules e.g. proteins
66
Q

circulation for fish

A

4-chambered heart
Gas exchange with water
Single circuit circulatory system
Low blood pressure in vessels leading to body (slow flow)
valves ensure 1 one flow

67
Q

The Windkessel effect - dampening large fluctuations in fish

A

Elasticity of the bulbus arteriosus dampens the large fluctuation of pressure from the ventricles (in fish)
Human major arteries like the aorta serve same function

68
Q

Characteristics of circulatory systems in vertebrates

A

3 chambered heart
Gas exchange w/ air
2 circuit circulatory system
Pulmonary & systemic circuits partially separated - mixed blood

69
Q

Characteristics of circulatory system in birds/mammals

A

4-chambered heart
Gas exchange w/ air
2 circuit circulatory system
Low blood pressure in vessels leading to lungs
High blood pressure in vessels leading to body (rapid flow)

70
Q

Evolution of vertebrate circulatory systems

A

Increased separation b/w blood flowing to the gas-exchange organs from blood that flows to body
- crocodilian right ventricle can pump to both pulmonary or systemic circuits - when crocodile is UNDERWATER, vessels in PULMONARY CIRCUIT constrict, increasing resistance

71
Q

Human circulatory system characteristics

A

4-chambered heart
Pulmonary & systemic circuits are separate
Different pressure in pulmonary & systemic circuit
Organs supplied in parallel, but liver takes blood directly from intestine
Walls of right ventricle are thinner than walls of left ventricle - because left ventricle must push out blood to body so higher pressure

72
Q

Role of pacemaker

A

Spontaneous generation of AP (action potential) by pacemaker cells at the sinoatrial node
Electrical signal spread across the atria via gap junctions resulting in coordinated contraction
Signal causes activation of the atrioventricular node
Electrical signal passes down modified cardiac fibers (Pukinje fibers)
Electrical signal spreads across the ventricles via gap junctions resulting in coordinated contraction

NOTE: THE CELLS OF THE sinoatrial node, atrioventricular node, & Pukinje fibers are all types of cardiac muscle cells

73
Q

Systole

A

ventricles contract, atria relax

74
Q

Diastole

A

ventricles relax, atria contract

75
Q

What powers blood flow through veins?

A

Blood flow through veins is powered by skeletal muscles & gravity

76
Q

Distinguish b/w arteries, veins & capillaries

A

Arteries: thick, elastic, & muscular - can support high pressures of blood leaving heart

Veins: have valves to ensure 1-way flow of blood returning to heart under low pressure

Capillaries: have very thin walls (1 cell thick) to allow diffusion

77
Q

Give a brief overview of gas exchange in the lungs

A

Air enters the lung through an arteriole & fills alveoli
Alveoli are covered by a network of fine capillary
Diffusion across thin alveoli & endothelial cells
Incoming blood has low concentration of O2 which diffuses in, & high concentration of CO2 which diffuses out

78
Q

water potential =

A

osmotic pressure + blood pressure

79
Q

Outline Starling’s Model

A

Pressure potential goes down from 40 mm Hg to 16 mm Hg from artery to vein
Osmotic potential stays constant at -25 mm Hg
Remains constant because of large molecules trapped within capillaries
Water potential is higher at artery than at vein
Water potential is higher outside the capillary bed than inside, so we get water flowing out from the capillaries into the interstitial fluid → FILTRATION at the artery
Water potential is higher inside the capillary bed at the vein, so reabsorption happens

Biology 1 (10 decks)

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