Chapter 49: Digestive and Excretory Systems

1
Chapter 49 Digestive and Excretory Systems
49-1 Nutrients
49-2 Digestive System
49-3 Urinary System
2
49-1 Nutrients
I. Six Basic Food Ingredients

• MOST foods contain a bulk of just ONE or TWO
  nutrient types.

3
(1) Nutrients (2 CLASSES (1) Organic (CPLV) (2)
inorganic (MW)

• Chemicals NEEDED for growth, maintenance, and
  metabolic activity.

4
Critical Thinking
(1) In some countries, many children suffer from
a type of malnutrition called kwashiorkor.
Symptoms include swollen stomachs and a tendency
to become increasingly thinner until they die.
Even when provided with RICE and WATER, these
children still cannot survive. What TYPE of
nutritional deficiency might these children
possess?
5
(A) Carbohydrates (e.g., mono-, di-, and
polysaccharides)

• Broken down (hydrolysis) to monosaccharides
  (glucose) to be used by cells during AEROBIC
  RESPIRATION to make ATP.

6
(No Transcript)
7
(No Transcript)
8
(B) Proteins (e.g., keratin, polymerase,
collagen, hemoglobin, lactase)

• Help with growth, reproduction, repair, and ALSO
  serve as ENZYMES (chemical reactions) NOTE
  essential and non-essential AA.

9
(No Transcript)
10
(No Transcript)
11
(C) Lipids (e.g., oils, waxes, saturated and
unsaturated fats)

• Cell MEMBRANE repair, insulation, protective
  padding, and serve as an NRG reserve (adipose
  tissue).

12
(No Transcript)
13
(No Transcript)
14
(No Transcript)
15
(D) Vitamins (e.g., Vitamin D is the only one
self-synthesized)

• Large, ORGANIC compounds work as COENZYMES ?
  activate true enzymes during our METABOLISM.

16
(No Transcript)
17
(No Transcript)
18
(E) Minerals (e.g., calcium, iron, potassium,
phosphorous, salts, iodine, zinc)

• INORGANIC substances needed for HEALTHY cellular
  functioning.

19
(No Transcript)
20
                             Food 2                                  Food 3                            
21
Critical Thinking
(2) Which of the SIX basic nutrients might a
person need to RESTRICT after an operation to
REMOVE the gall bladder? Explain your choice.
22
(F) Water

• MEDIUM for cellular RXNS, PLASMA (blood
  pressure), and used to REGULATE body temperature
  (heating/cooling).

23
(1) Dehydration (NOTE A 12 loss fatal)

• If water is LOST (and NOT replenished), then
  water will be DRAWN from ECM to blood (via
  osmosis)eventually cells lose water AND die.

24
(No Transcript)
25
(No Transcript)
26
(No Transcript)
27
(No Transcript)
28
(No Transcript)
29
(No Transcript)
30
(No Transcript)
31
49-2 The Digestive System
I. The Gastrointestinal Tract (a.k.a., alimentary
canal)

• G.I. TUBE ? mouth TO anus (excludes ACCESSORY
  organs ? liver and pancreas).

32
(No Transcript)
33
(A) Mouth

• Mechanical (mastication) AND chemical digestion
  (salivary amylases).

34
(1) Incisors and Molars

• EXPOSE larger SURFACE AREA for enzymes to ACT
  UPON.

35
(2) Hard Palate and Soft Palate (UPPER MOUTH)

• Bony region (FRONT), grinds food AGAINST SOFT
  tissue (BACK) separates mouth from NASAL cavity.

36
(3) Saliva (i.e., water, mucus, and
amylasebreaks down STARCHES)

• SOFTENS food for swallowing AND assists with
  digestion.

37
(B) Esophagus (i.e., food pipe circular AND
longitudinal smooth muscle)

• Delivers BOLIS (via peristalsis) from oral
  cavity TO stomach.

38
(1) Bolis (i.e., food BALL)

• Once chewed and moistened, food is ROLLED into a
  swallow-able ball.

39
(2) Epiglottis (separates esophagus-trachea)

• Flap of cartilage PREVENTS material from
  entering TRACHEA.

40
(3) Peristalsis (carried out by TWO smooth muscle
types)

• Involuntary, muscular CONTRACTIONS squeeze bolis
  through a VALVE into stomach. (NOTE defies
  gravity)

41
(C) Stomach (made of circular, longitudinal, AND
diagonal smooth muscles)

• Elastic, muscular sac ? MAXIMIZING mechanical
  (churning) and chemical (digestive acids)
  digestion 3-4 hours per meal.

42
(No Transcript)
43
(1) Gastric Pits (open ends of GASTRIC GLANDS
lining the stomach)

• Secrete MUCUS, digestive ENZYMES, and HCl ? mix
  to produce an ACIDIC fluid (pH lt 2).

44
II. Chemical Digestion

• Amylase (saliva), HCl (stomach), pepsin
  (stomach), other enzymes (intestines)liberate
  nutrients, allow for ABSORPTION into bloodstream.

45
Critical Thinking
(3) Some people CANNOT drink milk because they
are unable to digest LACTOSE, the sugar in milk.
Doctors believe this inability involves SPECIFIC
areas of the digestive system. What do you
suppose these areas are?
46
(1) Gastric Fluid (i.e., product of gastric pits)

• Responsible for CHEMICAL digestion in stomach
  (enzymes and acid).

47
(2) Pepsin (NOTE Converted from inactive
pepsinogen (needs LOW pH)

• Enzyme SPLITS large PROTEINS into SMALLER chains
  of amino acids (peptides).

48
(3) Ulcer (lesions recently attributed to some H.
pylori bacteria species)

• Mucous coating BREAKS down, allowing gastric
  fluid to DIGEST part of stomach epithelial lining.

49
(A) Formation of Chyme

• Mouth? Esophagus ? Cardiac Sphincter ? Stomach ?
  Pyloric Sphincter ? CHYME enters INTESTINES.

50
(1) Cardiac Sphincter (circular muscle BETWEEN
esophagus and stomach)

• Regulates what ENTERS or LEAVES stomach from
  esophagus.

51
(2) Chyme

• INTESTINAL PASTE of fats, sugars, starches,
  vitamins, minerals, peptides, and proteins (that
  were NON-affected by pepsin).

52
(3) Pyloric Sphincter (circular muscle between
stomach AND small intestine)

• Regulates FLOW of chyme into SMALL INTESTINE ?
  mixes with SECRETIONS from LIVER and PANCREAS.

53
II. Liver (NOTE Largest GLAND in the body)

• Makes BILE (emulsifies NOT digests fats), stores
  GLYCOGEN, and breaks down TOXINS in blood into
  harmless products (alcohol, ammonia).

54
(1) Gall Bladder (NOTE Cholesterol deposits can
lead to GALLSTONES)

• EXPANDS and STORES BILE to be secreted into S.I.
  during CHYME movement.

55
(C) Pancreas (digestive AND endocrine organ,
sodium bicarbonate, raises pH)

• Secretes fluid ? RAISES pH of chyme from acid TO
  baseactivates DIFFERENT enzymes inside intestine.

56
Critical Thinking
(4) A person has a small intestine that has villi
BUT lacks microvilli. Would you expect this
person to be underweight OR overweight? Explain.
57
(D) Small Intestine (i.e., duodenum-jejunum-ileum
22 feet long coil)

• FINAL site of digestion and where NUTRIENT
  ABSORPTION into bloodstream is MAXIMIZED (e.g.,
  villi and microvilli).

58
(1) Jejenum (MIDDLE section, 8 feet long)

• Mucus PROTECTS intestinal walls from
  protein-digesting enzymes.

59
(No Transcript)
60
(E) Absorption (large SURFACE AREA for nutrients)

• AA, glucose, and fatty acids are absorbed into
  BLOOD and LYMPHATIC vessels lining small
  intestine.

61
(No Transcript)
62
(1) Villi and Microvilli (fingerlike PROJECTIONS
of intestinal lining)

• INCREASE surface area of 21 FEET of intestines
  to SIZE of roughly a TENNIS COURT (absorb via
  diffusion and active transport).

63
(No Transcript)
64
(2) Lacteals (tiny LYMPH capillaries)

• LYMPH receives FATS ? eventually to bloodstream
  BLOOD receives AA and SUGARS ? liver ? FILTERS
  nutrient rich blood.

65
(No Transcript)
66
III. Large Intestine (4 regions ascending,
transverse, descending, sigmoid)

• Only minerals AND vitamins (bacteria made) and
  WATER are reabsorbed into bloodstream ELIMINATE
  feces, (solid remains of CHYME).

67
(No Transcript)
68
(No Transcript)
69
(No Transcript)
70
                             Food 2                                  Food 3                            
71
(No Transcript)
72
(No Transcript)
73
49-3 Urinary System
I. Kidneys (maintain HOMEOSTASIS of body)

• Regulating PRESSURE and pH of blood (water
  volume and solutes).

74
(No Transcript)
75
(A) Structure (paired organ)

• Kidney is subdivided into (1) CORTEX and (2)
  MEDULLA

76
(1) Cortex and Medulla

• OUTER (1/3) and INNER (2/3) regions of kidney.

77
(2) Renal Pelvis (EXTENSION of the ureter)

• Funnel-shaped structure in CORE of kidney (acts
  as a CHANNEL).

78
(No Transcript)
79
(3) Urea (product of PROTEIN metabolism)

• Nitrogenous waste product brought to liver as
  AMMONIA.

(4) Ammonia

• Removed from blood by liver and CONVERTED to
  urea, which enters bloodstream and is REMOVED by
  kidneys.

80
Critical Thinking
(5) When the kidneys stop functioning, urea
builds up in the blood and poisons the body. A
person with kidney failure will eventually die if
the urea is not somehow removed. For the urea to
be removed, the patient must be attached to an
artificial kidney, also called a dialysis
machine. Using your understanding of how a
normal kidney functions, what do you suppose this
machine is built to do/regulate?
81
(No Transcript)
82
(No Transcript)
83
(B) Nephron ( 1 MILLION per kidney, perform ALL
duties for urine)

• Functional unit of kidneys (Filtration,
  Reabsorption, Secretion)

84
(1) Urine (a mixture of products)

• Removed FROM blood (includes urea, water,
  toxins, mineral salts).

85
Critical Thinking
(6) Explain why a high concentration of protein
in the urine may indicate damaged kidneys.
86
(2) Bowmans Capsule (CUP-shaped structure)

• Encloses a CAPILLARY bed (i.e., glomerulus)
  where HIGH pressured DIRTY blood is RECEIVED
  (from the renal ARTERY).

87
(3) Glomerulus (enclosed INSIDE Bowmans Capsule
125 mL/minute)

• CAPILLARY BED that receives dirty blood from
  renal artery (FILTER).

88
(4) Renal Tubule PCT, Loop of Henle, DCT

• A long TUBE with PERMEABLE walls in nephron.

89
(No Transcript)
90
(C) Filtration (FORCES out urea, water, glucose,
vitamins, and salts)

• Materials from blood are forced OUT of
  glomerulus into Bowmans Capsule.

91
(No Transcript)
92
(No Transcript)
93
(No Transcript)
94
(D) Reabsorption and Secretion

• Materials RETURN to blood (ACTIVE transport) OR
  some materials PASS from blood to FILTRATE
  (secretion)

95
(No Transcript)
96
(1) Reabsorption (MOST occurs in PCT, some in DCT)

• 75 of WATER (in filtrate) returns BACK to
  BLOOD, in addition glucose and minerals ALSO
  returned to BLOOD.

97
(No Transcript)
98
(2) Secretion (when FILTRATE reaches the DCT)

• Wastes moved from BLOOD to FILTRATE, in
  addition, pH of the blood is ADJUSTED by
  secreting excess H ions.

99
Critical Thinking
(7) The loop of Henle functions to conserve water
by reabsorbing it. Its length varies among
mammal species. Would you expect the loop of
Henle of an animal like a dolphin to be longer or
shorter than that found in humans? Explain.
100
(E) Formation of Urine

• Fluids and wastes that REMAIN in DCT form URINE
  that flows into a COLLECTING DUCT (via osmosis).

101
(F) The Loop of Henle (between PCT and DCT)

• Maintains a HIGH NaCl in SURROUNDING fluid,
  driving water (via OSMOSIS) out of collecting
  duct (and BACK to the BLOOD).

102
(No Transcript)
103
(No Transcript)
104
(G) Elimination of Urine

• Urine from COLLECTING DUCTS drains into RENAL
  PELVIS and into a narrow tube (ureter).

105
(1) Ureter (1 for EACH kidney)

• Drains renal pelvis into URINARY BLADDER for
  storage of urine.

106
(2) Urinary Bladder (1 for BOTH kidneys)

• Muscular EXPANDABLE sac drains into urethra.

107
(3) Urethra (1 for BOTH kidneys)

• Tube EXITING urine from BODY.

108
(H) Excretory System (AIM To eliminate WASTES
from healthy cells)

• Includes kidneys, skin, and lungs, tightly tied
  into CIRCULATORY system.

109
(No Transcript)
110
(No Transcript)
111
(No Transcript)
112
(No Transcript)