Digestive and Muscular Systems Flashcards
(131 cards)
1
Q
What is Amylase?
A
An enzyme that breaks down complex carbohydrates (starches) into simpler sugars. It is secreted by both the salivary glands and the pancreas.
2
Q
What is protease?
A
An enzyme that breaks down proteins into smaller peptides and amino acids. This process is crucial for protein digestion and absorption.
3
Q
What is lipase?
A
An enzyme that breaks down fats into fatty acids and glycerol. This is essential for the absorption of fats and other fat-soluble vitamins.
4
Q
What is lactase?
A
An enzyme that breaks down the sugar lactose (found in milk) into glucose and galactose.
5
Q
What is maltase?
A
An enzyme that breaks down the sugar maltose into glucose.
6
Q
What is sucrase?
A
An enzyme that breaks down the sugar sucrose (table sugar) into glucose and fructose.
7
Q
What is pepsin?
A
A protease enzyme produced in the stomach that helps break down proteins.
8
Q
What is Trypsin and Chymotrypsin?
A
Protease enzymes produced by the pancreas that help break down proteins in the small intestine.
9
Q
What are macromolecules?
A
Large, complex organic molecules
10
Q
What are the four classes of macromolecules?
A
- carbohydrates
- lipids
- proteins
- nucleic acids
11
Q
What are polymers?
A
Large molecules formed by linking many subunits (ex. macromolecules)
12
Q
What are monomers?
A
Each repeating subunit of the polymer
13
Q
What is dehydration synthesis?
A
Reaction that assembles macromolecules
14
Q
How do monomers bond?
A
A hydroxyl group is removed from one subunit and a hydrogen atom (H) is removed from the other subunit; water is the byproduct.
15
Q
What is hydrolysis?
A
Reaction where macromolecules are disassembled by the addition of water
16
Q
What are the composition of carbohydrates?
A
Almost alwasy two atoms of hydrogen and one atom of oxygen for every atom of carbon (CH2O)n
17
Q
What are the function of carbohydrates?
A
Provide short and long term energy storage for organisms. Provide energy for the body’s metabolism
18
Q
What are the three types of carbohydrates?
A
- mono saccharides
- disaccharides
- polysaccharides
19
Q
What are mono saccharides?
A
Simple/energy sugars; crucial in the process of energy transfer within cells and among living systems (ex. glucose, fructose, galactose)
20
Q
What are disaccharides?
A
Double/transport sugars; made up of two monosaccharides through dehydration synthesis; transported through the body to where it is needed for energy or stored for later
21
Q
Examples of disaccharides?
A
- Sucrose (glucose + fructose)
- Lactose (galactose + glucose)
- maltose (glucose + glucose)
22
Q
What are polysaccharides?
A
Complex/storage/structural sugars; carbohydrates that consist of many linked simple sugars
23
Q
Examples of polysaccharides?
A
- starch/amylase: stores energy in plants
- glycogen: stores energy in animals
- cellulose: make up cell walls in plants
24
Q
What are lipids?
A
Used for energy storage; are components of cell membranes and play a role in hormone synthesis
- insoluble
- made mostly of C,H,O atoms
25
What are the three types of lipids?
Triglycerides, phospholipids, steroids
26
What are triglycerides?
Form when one glycerol reacts with three fatty acids
27
What are the two categories of fatty acids?
- Saturated Fatty Acids: contain maximum number of hydrogen atoms and are solid at room temperature; harder to digest (ex. butter, meat)
- Unsaturated Fatty Acids: Contain double bonds between some carbon atoms to allow additional hydrogen; liquid at room temperature; easier to digest (ex. vegetable or olive oils)
28
What are phospholipids?
Structural lipids found in most animal membranes including cell membranes
Composed of a hydrophilic phosphate head and hydrophobic fatty acid tail
(cell memranes are formed by these molecules forming tail to tail to form a phospholipid bilayer)
29
What are steroids?
Consist of four interconnected carbon rings; componenets of membranes or serve as vitamins and hormones (ex. vitamin D, estrogen, testosterone)
30
What are the three essential functions of proteins?
-Structural Support: major component of bone, cartilage, geathers, fur, hair
- Enzymatic Catalysts: all enzymes are proteins (play role in growth and function)
- Transport and Storage: carrier or many important small molecules and ions
31
What are amino acids?
Subunits of proteins
32
What does each amino acid consist of?
1. central carbon atom bonded to Hydrogen atom
2. amino group
3. caboxyl (acid) group
4. R group
33
What is a R group?
Determines identity and distinguishes twenty types of amino acids from one another
34
What are essential amino acids?
nine of the twenty types; cannot be synthasized and must come from diet
35
How are protein shapes made?
- amino acids bond together in strands to form proteins and are connected by peptide bonds via dehydration synthesis
- different amino acids attract and repel so the strand coils and twists
- creates complex 3D structure (determines properties and functions of the protein)
36
What can proteins undergo due to their complex 3D shapes?
Denaturation and deamination
37
What is denaturation?
The protein loses its teritary and secondary structures by application of some external stress (ex. protein albumin in egg whites)
38
What is deamination?
Protein loses its tertiary and secondary structures by the removal of amino groups. facilitated by enzymes called deaminases (done to breakdown excessive amino acids if no carbohydrates or lipids are there to burn as energy)
39
What is nucleic acid?
Determine how a cell functions and what characteristics it has (made up of subunit: nucelotides)
40
What are the two types of nucleic acid?
- DNA
- RNA
41
How are DNA and RNA different?
Both are made of a phosphate group, and a nitrogenous base. The five carbon sugar is deoxy or ribose, determining whether it is DNA or RNA)
42
Why are catalysts needed within the body?
- all macromolecules can be used for chemical reactions in the body
- these reactions may occur too slow to be useful though
- raising temperature could increase the rate of reactions, but the temperatures at which they occur are so high they would permanently denature body proteins
- using catalysts can speed up and lower energy required for chemical reactions (also aren't used up in the reaction)
43
What are enzymes?
Specialized protein molecules that function as biological catalysts
44
Example of enzyme bonding?
1. glucose and fructose bond to make sucrose
2. substrate sucrose binds to the active site of an enzyme (sucrase)
3. water is added
4. the bond between glucose and fructose is broken
5. products are released and the enzyme is free to bind another sucrose substrate
45
What are enzymes affected by?
Temperature and pH
- specific enzymes have optimal functioning ranges for both
- enzymes will notbe flexible enough to fit hte subtrate if the temperature is too low and will denature if the temperature is too hgih
46
What are inhibitors?
Molecules that attach to the enzyme and reduces its ability to bind substrate
47
What are the two types of inhibitors?
- competitive inhibitors
- non competitive inhibitors
48
What are competitive inhibitors?
Both the the ibhibitor and substrate compete to occupy the active site; if the inhibitor is present in high enough concentrations, enzymes activity is inhibited completely
49
What are non-competitive inhibitors?
The inhibitor attaches elsewhere on the enzyme; this changes the shape of the enzyme which makes it less able to bind substrate
50
What is the digestive system?
gastrointestinal tract; open system 6-8m long located mostly in the abdominal cavity
51
What are the four main steps of processing food?
1- ingestion
2- digestion (mechanical/chemical)
3- absorption
4- egestion
52
What are the parts of the digestive system?
1- oral cavity (tongue, teeth, salivary glands, pharynx and epiglottis)
2- esophagus
3- stomach
4- small intestine (liver, gallbladder, pancreas)
5- large intestine (colon, appendix, rectum)
6- anus
53
What is done in the mouth?
ingestion
54
What do the teeth do?
starts mechanical digestion by chewing the food (increases surface area available for chemical digestion)
55
What is the bolus?
Lump-like mass food is rolled into by the tongue, which is pushed to the back of the mouth for swallowing
56
What is the saliva?
facilitates swallowing, activates the taste buds, contains enzyme (salivary amylase) which starts chemical digestion (specifically starts breaking down carbohydrates)
57
What is the pharynx?
The throat (shared by the digestive and respiratory system); the bolus passes through it for swallowing
58
What is the epiglottis?
Flap of tissue that prevents food from entering your trachea; closes as the bolus passes by
59
What is the esophagus?
muscular portion of the digestive tract that directs food from the motuh to the stomach
- the bolus moves partly by gravity but mainly through peristalisis
60
What is peristalsis?
Wave-like series of mucular contractions and relaxations
61
What is the cardiac sphincter?
Ringlike muscular structure that controls entry into the stomach; prevents acidic contents of the stomach from backing up into the esophagus
62
What three functions does the stomach have?
- storage
- digestion (mainly mechanical, some chemical)
- pushing food (into small intestine)
63
How does the stomach use peristalsis?
The three layers of muscle use peristalsis to make chyme
64
What is chyme?
acidic mixture of food made in the stomach
65
What is rugae?
Muscular folds inside the stomach that increase the surface area for digestion adn aid in the mixing; allows the stomach to expand
66
What are the few substances that can be absorbed from the stomach to the blood syste,?
Water, salts, anti-inflammatories (ex. aspirin)
67
What are gastric pits?
Located at the bottom of the rugae, comprised of three main types of cells; produce 2-3 L of gastric juice daily
68
What are the three types of cells that make up gastric pits?
- parietal cells
- mucous cells
- peptic/chief cells
69
What are parietal cells?
- secrete HCL (hydrochloric acid) into the stomach daily
- create an acidic environment i n the stomach (1-3pH)
- helps dissolve through tissues, activate enzymes, kill pathogens
70
What are mucous cells?
- secrete mucous
- create protective barrier on the stomach lining from acidic juices and digestive enzymes
71
What are peptic/chief cells?
- secrete inactive enzymes (pepsinogen) that is activated by HCl to become pepsin
- begins protein digestion
72
How is secretion stimulated in the stomach?
Proteins in food stimulate secretion of stomach hormone (gastrin) which stimulates secretion of HCl and pepsinogen
73
Can you live without a stomach?
- stomach aids in some digestion only (mostly used for storage and pushing food into the small intestine)
- so yes, you could
gastrectomy = removal of a stomach
74
Why is the small intestine called "small"
Because of wits witdth/diameter
75
What happens in the small intestine?
- chyme leaves the stomach by the pyloric sphincter and enters the small intestine
- lots of chemical digestion happens
76
What are the three main sections of the small intestine?
- duodenum
- jejunum
- ileum
77
What is the duodenum?
- widest portion, most chemical digestion
- requires variety of enzymes made in the small intestine
- the pancreas and liver and gall bladder (accessory organs) also create enzymes
78
What is the jejunum?
- 2.5m-ish long
- has more folds and secretory glands than the duodenum
- continues breakdown of food so products can be absorbed
79
What is the ileum?
- 3m-ish long
- absorbs nutrients and pushes remaining undigested material into large instestine
80
What does the pancreas do?
- delivers 1L pancreatic fluid to deuodenum (contains enzymes)
- also contains sodium bicarbonate which neutralizes the HCl entering the duodenum (brings small intestine's pH to optimal 8)
81
What does the liver do?
- produce bile (greenish-yellow fluid)
- conduct a from of physical digestion that emulsifies fats so water soluble lipases have a larger surface rea to act upon
82
Where does the bile go from the liver?
- produced in the liver then sent to gall bladder for storage between meals
83
What happens in the gallbladder?
- arrival of fat-containing chyme in the duodenum stimulates the gall bladder to contract, injecting bile into the duodenum via bile duct
- achieved by hormone regulation
84
What are villi?
Finger-like projections that line the ridges of teh inner surface of the small intestine
85
What are micro-villi?
Microscopic extgension s of villi; site of absorption
- each micro-villi is laced with capillary networks and lymph vessels that take absorbed substances into the bloodstream and lymphatic system
86
What happens to smaller and larger molecules in the small intestine?
- smaller molecules are absorbed into the blood system
- larger molecules are absorbed into the lymph system
87
What happens to monosaccharides and amino acids in the small intestine?
Absorbed into the villi by active transport then diffused into blood vessels
88
What happens to glycerol and fatty acids in the small intestine?
Diffuse into the villi; are reassembled into triglycerides, coated with proteins (make them soluble) to enter lymph vessels. Once in the bloodstream, the protein coating is removed and triglycerides are hydrolyzed into fatty acids and glycerol by lipase in the blood
89
What does the large intestine do?
Recieves material remaining in small intestine after absorption, concentrates and eliminates waste materials. indigestible chyme is reduced and aided through the colon through lubrication by mucous secretions
90
What is the caecum?
First part of the colon, directly connected to the appendix
91
What is the appendix?
- though to be useless, recently show it may be a haven to beneficial bacteria in the colon when illness flushes them out
- billions of beneficial anaerobic bacteria in the colon help break chyme further
- also produce B12 and K vitamins
92
What What occurs in the rectum and anus?
- any remaining indigestible chyme and and colon bacteria form feces that pass into the rectum and the anal canal
- feces distends rectal walls, causing nervous system to start bowel movements (via peristalsis)
93
How is the anus controlled?
Has two sphincters. You control the ot=uter sphincter, and the narvous system controls the inner anal sphincter
94
What are ulcers?
- occurs in stomach/duodenum
- mucous breaks down, cell membranes are exposed to acid and enzymes
- 80% caused by bacteria (helicobactor pylori), 20% by other (smoking, alcohol, stress, etc)
95
How can ulcers be treated?
- medications to reduce amount of acid or strengthen mucous layer
- antibiotics
- lifestyle changes
96
What is hepatitis?
Inflamation of the liver caused by three types of viruses (A, B, C)
97
What is hepatitis A?
usually contracted frp, drinking contaminated water
98
What is hepatitis B?
Spread by sexual contact
99
What is hepatitis C?
Caught by contact with infected blood (can be self-limiting or progress to fibrosis and/or cirrhosis)
100
What is sirrhosis?
Chronic disease that occurs when scar tissue replaces healthy liver tissue and prevents it from functioning properly
- alcoholism and hepatitis are the most common causes
- has few symptoms and can lead to liver failure
101
What are gallstones?
- small hard masses formed in the gall bladder
- cholesterol can precipitate out of the bile and form crystals that grow in size and become gallstones
- influenced causes are obesity, alcohol, heredity
102
What is the treatment for gallstones?
- medication
- ultrasound shock waves to disintegate them
- entire gall bladder may need to be removed
103
What are muscles?
Tissues that act by contracting
104
What are the three types of muscles?
- cardiac
- skeletal
- smooth
105
What is cardiac muscle?
- striated
- tubular and branched
- one nucleus
- contract involuntarily
- found in the walls of the heart
106
What is smooth muscle?
- non striated
- one nucleus
- contract involuntarily
- found in hollow partts of the body (ex. organ linings, uterus, walls of arteries)
107
What is keletal muscle?
- striated and tubular
- many nuclei
- contract voluntarily
- usually attached to bones of the skeleton
108
Why can muscles only pull and not push?
when they contract they shorten
109
How do muscle contractions usually work?
Usually occur in pairs (one contracting, one relaxing)
110
What is the hierarchy of skeletal muscles ?
muscle, muscle fibre bundle, muscle fibre, myofibrils, myofilaments
111
What is a tendon?
Heavy band of tissue made mainly of collagen that attaches each skeletal muscle at both ends to a bone
112
What are fascicles?
Muscle fibre bundle; bundles of muscle fibre that make up muscle
113
What are myofibrils?
Subunits of muscle fibres
114
What are sarcomere?
Contractile unit of a myofibril
115
What are myofilaments?
Make up myofibril; contain protein structures that are responsible for muscle contractions and have two types (actin and myosin)
116
What are actin?
thin; consist pf twp strands of protein molecules that are wrapped around each other
117
What are myosin?
Thick; consist of two strands of protein molecules wound around each other but has a different shape; one end consists of a long rod and the other consists of a double-headed globular region
118
What is the process of a muscle contraction?
- the myosin head moves in a backward and inward motion
- moves them a few nanometers in the direction of the flex and pulls the attached actin with it
- myosin releases the actin and unflexes (powered by ATP)
- process repeats and actin slides past the myosin (sliding filament model of muscle contraction)
- each actin is anchored at one end at the z line (edge of each sarcomere)
- as actin moves past myosin it drags the z line toward the myosin
- one actin being pulled inward in one direction and the other n the opposite direction, the z line moves toward each other as they slide past the myosin core
119
What is rigor mortis?
Muscles contract and stiffen after death as there is no ATP present
120
What does calcium do in muscle contraction?
- when myosin head are raised and ready to attach, they are unable to since the attachment sites are blocked by tropomyosin (protein)
- the calcium binds to another protein on the actin (troponin)
- this repositions the tropomyosin proteins adn exposes the myosin binding sites on actin
- now it can bind and contraction occurs
121
What are the three ways muscles obtain ATP?
- aerobic cellular respiration
- lactate (lactic acid) fermentation
- breakdown of creatine phosphate
122
What is the breakdown of creatine phosphate?
- used first to acquire ATP before the oxygen enters the mitochondria for aerobic cellular respiration
- creatine phosphate is a high energy compound that builds up when a muscle is resting
- reaction occurs wihtin the myofilaments
- speediest way to make ATP for muscles but only provides about 8 seconds of intense activity (then rebuilt when muscle is resting)
123
What causes muscles to contract?
Electrical impulses from the nervous system, each muscle fibre has a minimum voltage required to cause it to contract
124
What is the all-or-nothing response?
If the minimum voltage threshold is reached, the fibre will contract; won't contract "harder" or "faster" with more voltage
125
What is a muscle twitch?
The single contraction (lasts a fraction of a second)
126
What are the three periods of a muscle twitch?
1) latent period- period of time between stimulation adn initiation of contraction
2) contraction period- when the muscle shortens
3) relaxation period- when the muscle returns to its former length
127
Doesa muscle follow the all-or-nothing approach?
No; a single muscle fibre contracts in an all-or-nothing approach, but an entire muscle contraction can vary in strength depending onthe number of muscle fibres contracting in it
128
What is summation?
If a muscle is given a rapid series of
threshold stimuli, it can respond to the
next stimulus without relaxing completely.
In this way, successive twitches partially
“ride piggyback” on each other in a
cumulative response called summation,
129
What is tetanus? (not the disorder)
Maximal sustained contraction
130
What are slow twitch fibres?
Tend to be aerobic; fibres contract slowly
but resist fatigue (that is, they have more
endurance).
131
What are fast twitch fibres?
Tend to be anaerobic; fibres are adapted for the
rapid generation of power.
