Chapter 6- Human Physiology Flashcards

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1
Q

Name the structure of the small intestine from outward to inward.

A

Serosa
Longitudinal Muscle [SMOOTH MUSCLE] (Helps make it longer)
Circular Muscle [SMOOTH MUSCLE] (Helps squeeze it)
Submucosa
Mucosa
Lumen (lined with Villi)

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2
Q

Serosa

A

An outer coat = Tough/ Flexible/ Strong/ Surrounding outside (where pancreas is)

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3
Q

Submucosa

A

Tissue layer containing blood and lymph vessels.

Connective tissue betw. mucosa and muscle layer

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4
Q

Mucosa

A

The lining of the small intestine, w. epithelium that absorbs nutrients on its inner surface.

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5
Q

Mesentry

A

Hanging part of the small intestine = has the blood supply and nerve supply

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6
Q

What does the contraction of circular muscle behind the food do?

A

Constricts the gut = prevents it from being pushed back to the mouth.

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7
Q

What does the contraction of longitudinal muscle where the food is located do?

A

Moves food along the gut.

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8
Q

What is the main funct. of peristalsis in the intestine?

A

Churning of semi digested food to mix it w. enzymes and speeds up the digestion process.

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9
Q

Endocrine glands (in pancreas) what are they and what do they secrete?

A

Secretes Insulin and Glucagon (hormone) INTO THE BLOOD.

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10
Q

Exocrine glands (in pancreas) what are they and what do they secrete

A

Synthesis and secretes digestive enzymes INTO THE GUT in response to eating a meal.

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11
Q

What are contractions of muscles controlled by?

A

Enteric Nervous System

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12
Q

What is the name of the cell that secretes digestive enzymes?

A

Acinar cells

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13
Q

Enzymes secreted by the pancreas.

A
\+ Amylase 
\+ Lipase 
\+ Protease 
\+ Phospholipase 
\+ HCO3 (Hydrogen carbonate) Buffer
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14
Q

Why is the hydrogen carbonate an essential secretion from the pancreas?

A

The pH int he stomach = low cuz of the HCl
+ before it enters the intestine = needs to be made to abt pH 7 so it doesn’t corrode the cell lining of the small intestine.

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15
Q

Amylase digests?

A

Starch into Maltose

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16
Q

Lipase digests?

A

Triglycerides into:
+ Fatty acids and glycerol
+ Fatty acids and monoglycerides

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17
Q

Phospholipase digests?

A

Phospholipids into:
+ Fatty acids
+ Glycerol
+ Phosphate

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18
Q

Protease digests?

A

Proteins and Polypeptides into:

+ Shorter peptides

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19
Q

What form are most of the enzymes secreted by the small intestine in?

A

Immobilised in the plasma membrane of epithelium cells lining the intestine.
They are active there an continue to be active when epithelium cells = scraped away, off the lining and mixed w. semi digested food.

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20
Q

Nucleases digest? (Synthesised by small intestine)

A

DNA and RNA into Nucleotides

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21
Q

Maltase digests? (Synthesised by the small intestine)

A

Maltose into Glucose

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22
Q

Lactase digests? (Synthesised by the small intestine)

A

Lactose into Glucose and Galactose

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23
Q

Sucrase digests? (Synthesised by the small intestine)

A

Sucrose into Glucose and Fructose

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24
Q

Exopeptidase and proteases digests? (Synthesised by the small intestine)

A

peptides into dipeptides

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25
Q

Depeptidase digests? (Synthesised by the small intestine)

A

Dipeptides into amino acids

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26
Q

What does Villi do to the small intestine?

A

Increases the surface area of epithelium of which absorption = carried out.

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27
Q

Absorption

A

The process of taking substances into the cell and the body.

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28
Q

For nutrients to be absorbed into the body, what must it first be absorbed into?

A

The epithelium cells through the exposed part of a plasma membrane that has a surface area enlarged w. micro villi.

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29
Q

Once the nutrients pass into the epithelium cell from the lumen of intestine, where does it go?

A

Absorbed into the lacteal (part of lymphatic system)(fats) or into the blood capillaries.

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30
Q

What are the 4 different mechanisms that move nutrients into and out of the villus epithelium cell?

A
  1. Simple diffusion
  2. Facilitated diffusion
  3. Active transport
  4. Exocytosis
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31
Q

How are triglycerides absorbed into the body?

A
  1. They must be digested = fatty acids and monoglycerides
  2. 1 Monoglycerides can be absorbed into the villus epithelium cell by SIMPLE DIFFUSION
  3. 2 Fatty acids absorbed by FACILITATED DIFFUSION via Fatty acid transporters (protein channels)!
  4. Inside the epithelium cell = fatty acids and monoglycerides combine = triglyceride = can’t diffuse back into lumen.
  5. Triglycerides = combine w. cholesterol to form droplets = become coated in phsopholipids and proteins = LIPOPROTEIN.
  6. Lipoprotein = released by exocytosis through plasma membrane on inner side of villus
  7. Either enter lacteal OR enter blood capillaries
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32
Q

Why can’t glucose enter the plasma membrane by ‘simple diffusion’?

A

Its POLAR = its hydrophilic!

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33
Q

How is glucose absorbed into the body?

A
  1. Sodium-Potassium pumps (on the inwards facing parts of the plasma membrane) = PUMPS 3Na+ ions by ACTIVE TRANSPORT from cytoplasm to the interstitial spaces inside the villus and 2K+ ions the opposite way!
  2. Sodium-Glucose co-transporter proteins in the (micro villi) = transfer a Na+ ion and a glucose molecule together from the intestinal lumen to the cytoplasm of epithelium cells
    THIS is a passive FACILITATED DIFFUSION that depends on the conc. grad of Na+ ions created by active transport.
  3. Glucose channels allow FACILITATED DIFFUSION of glucose from cytoplasm into the interstitial spaces inside the villus then into the blood capillaries.
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34
Q

Pinocytic vesicles contain?

A

Liquid

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35
Q

Phagocytic vesicles contain?

A

Solid

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36
Q

What does starch digestion in the small intestine illustrate?

A

+ Catalysis
+ Enzyme specificity
+ Membrane permeability

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37
Q

Properties of arteries (2)

A

1) Elastic Tissues in the wall
→ elastin fibres = store energy that stretches them at peak of each pumping cycle = recoil helps propel blood down artery
2) Smooth muscles contractions in artery walls determine diameter of lumen

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38
Q

List artery walls from outside in (3)

A

1) Tunica Externa = tough outer layer of connective tissue
2) Tunica Media = thick layer containing smooth muscles and elastic fibres
3) Tunica intima = Smooth endothelium forming the lining of artery

39
Q

Peak pressure in the arteries

A

+ Systolic pressure = pushes the walls of the arteries outwards = widening the lumen and stretching the elastic fibres int he wall = stores potential energy

40
Q

At the end of each heartbeat what happens to the pressure in the arteries?

A

+ Falls sufficiently for the stretched elastic fibres to squeeze blood in the lumen
→ Mech. saves energy and prevents the min. pressure in the artery = diastolic pressure in being too low

41
Q

Vasoconstriction

A

When circular muscles in wall of artery contracts

42
Q

How wide are capillaries?

A

10μm smallest blood vessel

43
Q

Features of capillaries

A

+ Endothelium cell = 1 cell thick
+ Walls v. permeable
+ Fenestrations allow plasma to leak out

44
Q

What is blood flow in veins assisted by? (2)

A

1) Gravity

2) Pressure exerted by other surrounding tissues

45
Q

Why are there valves in the veins?

A

Because bp is too low = danger of backflow

→ valves = prevent backflow

46
Q

How many flaps does a vein have and what shape?

A

3 cup-shaped

47
Q

2 circulations of the heart

A

1) Pulmonery circulation = to and from the lungs (RHS)
→ blood capillaries in lungs can’t withstand high pressure = blood pumped from heart at low pressure
2) Systemic circulation = to every else in the body
(LHS)
→ high pressure system

48
Q

Consequence of coronary occlusion (2)

A

+ Lack of oxygen = causes pain = Angina
→ impairs ability of heart to contract = heart beats faster to maintain blood circulation around body
+ Fibrous cap of arthroma = sometimes ruptures!
→ stimulates the formation of blood clots = block arteries to heart

49
Q

How to fix Coronary Occlusion (3)

A

1) Warfarin (Rat Poison!) = med. that prevents vlood clot from forming
2) Diet controlling = reducing LDL’s
3) Heart bypass surgery

50
Q

Medulla oblongata contains what that monitors the sinoatrial node

A

Cardiovascular centre

→ with sympathetic and parasympathetic nerves stemming out from it

51
Q

What does the cardiovascular centre receive?

A

Input from receptors that monitor:
+ bp
+ pH which shows CO2 conc.
+ O2 conc.

52
Q

What does ventilation do?

A

Maintains the conc. grad of oxygen and carbon dioxide betw/ air in the alveoli and blood flowing in adjacent capillaries

53
Q

Gas only diffuses when?

A

There’s a conc. grad

54
Q

What has to be done to maintain the conc. grad?

A

fresh air must be pumped in and stale air pumped out

55
Q

For gas exchange to be efficient what has to happen?

A

A conc. grad needs to be maintained in the alveoli

56
Q

Breathing in (conc. grad)

A

increases the conc. grad of the oxygen betw/ the alveoli and the blood
→ O2 diffuses into blood

57
Q

Breathing out (conc. grad)

A

decreases the conc. grad of CO2 betw/ the blood and alveoli

→ CO2 diffuses out

58
Q

Why are there rings of cartilage in the trachea?

A

To stop the tubes from collapsing when you turn your head

59
Q

What does the plural fluid do?

A

Stops the ribcage and lungs rubbing against e.o

60
Q

Adaptations to aid gas exchange (5)

A

1) Large surface area of lungs → alveoli
2) Thin cell wall of alveoli = allows fast rate of gas exchange
3) Good blood supply → maintains a high conc. grad
4) Warm
5) Moist/damp = allows gas to dissolve
→ and evaporated and be exhaled

61
Q

Type 1 pneumocytes

A

+ Extremely thin alveolar cells
→ adapted to carry out gas exchange
+ Lungs contain a huge # of alveoli w/ v. large s.a for diffusion

62
Q

What does the wall of the alveolus consist of ?

A

a single layer and cells = epithelium cells
→ most of them are type 1 pneumocytes
= flattened cells w/ thickness of 0.15μm of cytoplasm!

63
Q

Type II pneumocytes

A

+ round cells that occupy abt 5% of the alveolar s.a

→ secretes fluid containing SURFACTANTS that coat the inner surface of alveoli

64
Q

What does the fluid do to help gas exchange?

A

+ Allows for O2 in alveoli to dissolve then diffuse into the blood in alveolar capillaries
+ Provide area for CO2 to evaporate into air and be exhaled

65
Q

What is the structure of surfactants?

A

Similar to phospholipids in cell membranes
+ forms a MONOlayer on surface of moisture lining the alveoli
→ Hydrophilic heads facing water
→ Hydrophobic tails facing air

66
Q

What does surfactants do in the alveoli?

A

+ reduces surface tension and prevents water from causing the sides of the alveoli to adhere to e.o when air = exhaled
prevents collapsing of lungs

67
Q

Causes of lung cancer (5)

A

1) Smoking/tabacco/tar → caruses abt 87% of cases
2) Passive smoking → causes abt 3% of cases
3) Air pollution → causes abt 5% of lung cancer
→ most sig = diesel exhaust fumes/nitrogen oxides/smoke from burning coal, wood, organic matter
4) Radon gas → radioactive gas = leaks out of certain rocks s.a granite = accumulates in badly ventilates buildings and ppl inhale
5) Asbestos ,silica, other solids → cause lung cancer if dust/ other particles and them inhaled
→ usually in construction sites/ quarries/ mines/ factories etc.

68
Q

Consequences of lung cancer (7)

A
\+ difficulty breathing
\+ persistent coughing
\+ coughing up blood
\+ chest pain
\+ loss of appetite
\+ weight loss
\+ general fatigue
69
Q

What are the characteristics of the lungs of people w/ Emphysema?

A

→ smaller # of alveoli + larger air sacs w/ much thicker walls!
→ totals s.a for gas exchange reduced
→ dist. over which diffusion of gases occur increases
→ Gas exchange = less effective + lungs become less elastic and harder to ventilate

70
Q

What happens in the lungs of people that have Emphysema? (3)

A

+ Phagocytes inside the alveoli = normally prevent lung infections by engulfing bacteria and producing elastase (Protein digesting enzymes)
→ to kill them inside the vesicles formed by endocytosis
+ Enzyme inhibitor = alpha - 1 antitrypsin (A1AT)
→ usually prevents elastase and other proteases from digesting lung tissue
+ In smokers = the # of phagocytes in the lungs increase = produces more elastase
+ Genetic factors affect the quantity and effectiveness of A1AT made in the lungs
+ in abt 30% of smokers → digestion of proteins in alveolus wall by increase quantity of protease = not prevented by A1AT
→ walls are weakened and destroyed!

71
Q

Emphysema and the results of the damage

A

Chronic damage to the alveoli = usually irreversible
+ Causes Low O2 sat. in blood and higher than normal CO2 conc.
Result:
+ patients lacks energy
+ ventilation = labored and tends to be more rapid than normal

72
Q

What are the region of endocrine tissues in the pancreas called?

A

Islet of Langerhans

73
Q

What happens to Leptin in Obese ppl?

A

+ Have HIGH blood Leptin conc.

74
Q

What happens to target cells in the hypothalamus to leptin in obese ppl?

A

+ May become resistant to Leptin = fail to respond to it

75
Q

Where is Melatonin secreted?

A

Pineal gland

76
Q

What does Melatonin control?

A

Circadian rhythms

77
Q

What group of cells does the Circadian Rhythm depend on? (located in Hypothalamus)

A

Suprachiasmatic nuclei (SCN)

78
Q

When is Melatonin secretion elevated?

A

In the evening before bed = arouses sleepiness

79
Q

When does Melatonin levels fall?

A

At the end of the night = at dawn

→ The hormone is rapidly removed from the blood by liver

80
Q

How does melatonin contribute to body temp at night?

A

Causes the core body temp to fall

81
Q

What does melatonin receptors in the kidney suggest?

A

Decrease urine production at night = affected by melatonin

82
Q

What are the names of the special cells in the retina that is involved w/ regulating circadian rhythms?

A

Ganglion cells

83
Q

What do the Ganglion cells do?

A

They detect light at 460-480 nm = pass impulse to cells in the SCN
→ indicates to the SCN the timing of dusk and dawn = allows it to adjust the Melatonin secretion to correspond w/ day-night cycle

84
Q

The cause of Jetlag

A

+ The SCN and pineal gland = continuing to set the circadian rhythm to correspond to the timing of day-night at the time of departure rather than the time of destination

85
Q

If what gene is present on the Y chromosome then the embryonic gonads will develop to testes?

A

SRY

→ Codes for a DNA binding protein = TDF (Testes determining factor)

86
Q

What does TDF (Testes Determining Factor)do?

A

Stimulate the expression if other genes that cause Testis development

87
Q

The process of IVF ()

A

1) Down Regulation
→ women takes drugs everyday (nasal spray)
= stops pituitary glands from secreting FSH or LH
= secretion of Oestrogen and Progesterone stops
→ Suspends the normal menstrual cycle so doctors can control timing and amt of eggs made in ovaries
2) Artificial Hormone
→ intramuscular injections of FSH and LH = given daily for 10 days = stimulates follicle dev.
FSH given at higher conc. than Normal menstrual cycle = SUPRAOVULATION
3) When the follicles 18mm in diameter = stimulated to mature = injection of HCG
4) Micropipette mounted on an ultrasound scanner →
→ passed through uterus wall to wash out eggs out of follicles
5) Each egg = mixed w/ 50,000-100,000 sperm cells in sterile conditions in shallow dish
→ incubated at 37°C the next day
6) If fertilisation successful
→ one/more embryos = placed in the uterus when they are 48hrs old
→ Cuz women = not go through normal cycle = tablet of progesterone = placed in vagina to ensure endometrium maintained!

88
Q

Where does MOST starch breakdown happen?

A

In the small intestine w/ pancreatic amylase

89
Q

Which bond in starch can amylase break down?

A

1,4 bond (Amylose)

→ as long as there are at lease 4 glucose monomers

90
Q

Amylose is digested in how many glucose fragments and their names?

A

2-3 glucose fragments

Maltose and Maltotriose

91
Q

Why can’t Amylose breakdown 1,6 bond in Amylopectin?

A

Because of the specificity of the active site

92
Q

What are the segments of 1,6 bonds in amylopectin called?

A

Dextrin

93
Q

What are the 3 enzymes that complete the digestion of starch and what do they digest?

A

1) Maltase digests maltose
2) Glucosidase digests maltotriose
3) Dextrinase digests dextrins