Module 3: GIT Flashcards
1
Q
How much saliva do we create everyday?
A
~1500ml
2
Q
What is the name of the stomach rumble?
A
Borborygmi sounds
3
Q
How much fluid can a stomach hold?
A
~1500-2500ml
4
Q
What is the longest part of the GIT?
A
Small intestine
5
Q
What are the 2 properties of digestion?
A
- Physical
- Chemical
6
Q
What is an example of physical digestion of the GIT?
A
- Mastication
- Peristalsis
7
Q
What is the chemical digestion of the GIT?
A
The enzymatic breakdown of foods, e.g. salivary amylase
8
Q
Define the GIT
A
The breakdown of large molecules into small, water soluble molecules to allow for absorption into the blood and to be transported to organs
9
Q
What is peristalsis?
A
The rhythmic wave that pushes food through the canal
10
Q
Why are there sphincters in the GIT?
A
To facilitate unidirectional flow of food, in an antigrade direction
11
Q
What are the accessory glands of the GIT?
A
- Salivary
- Pancreas
- Liver
- (Defunct) appendix
12
Q
What does the GIT cover?
A
A closed circuit from mouth to anus
13
Q
Which 2 parts of GIT do not directly take part in digestion?
A
- Oesophagus: moves food from pharynx to stomach
- Appendix: not in use in humans
14
Q
What are the 2 directions of peristalsis?
A
- Antigrade: mouth to anus (preferred)
- Retrograde: vomiting
15
Q
What is antigrade movement in the GIT?
A
Movement of molecules from mouth to anus
16
Q
What is retrograde movement in the GIT?
A
Movement of molecules from anus to mouth, most common is vomiting.
17
Q
What is the role of the liver and the pancreas in the GIT?
A
To secrete digestive enzymes into the GIT: bile and pancreatic juices
18
Q
How is enzymatic release controlled from the liver and pancreas?
A
Via sphincters
19
Q
Are sphincters open or closed during eating?
A
Open
20
Q
Are sphincters open or closed when not eating?
A
Closed
21
Q
What are the 7 layers of the GIT (out to in)
“Silly Luke Must Chew Salty M & Ms”
A
- Serosa
- Longitudinal muscle
- Myenteric plexus
- Circular muscle
- Submucosal plexus
- Muscularis mucosa
- Mucosa
22
Q
What are the myenteric and submucosal plexus’?
A
Nerves
23
Q
What does the submucosal plexus innervate?
A
The control of secretion of mucus from the mucosa cells
24
Q
What does the myenteric plexus innervate?
A
Controls the muscles for contraction and relaxation to enable peristalsis
25
What are the 3 cell types of the mucosa?
1. Epithelial cells
2. Lamina propria
3. Muscularis mucosa
26
What are the 3 parts of the submucosa?
1. Circular muscle
2. Longitudinal muscle
3. Nerve plexuses
27
What are the intrinsic enteric nerves system in the GIT?
1. Submucosal plexus
2. Myenteric plexus
28
What are the extrinsic enteric sysems?
1. Parasympathetic: vagus T2
2. Sympathetic: pelvic L8
29
What are the 3 parts of the gut?
1. Foregut
2. Midgut
3. Hindgut
30
What parts of the body does the foregut cover?
From the oral cavity to the initial part of the duodenum, as well a the liver and pancreas
31
What part of the body does the migut cover?
Duodenum to initial 2/3 of the transverse colon (submesenteric artery)
32
What part of the hindgut does the body cover?
The later 1/3 of the transverse colon to upper part of the anus (infmesenteric artery)
33
What is in saliva?
1. Mucin
2. Buffers (HCO3)
3. Antibacterial enzymes (lysosyme)
34
What does amylase do?
Hydrolysis starch and glycogen to snake polysaccharides and maltose
35
What does the tongue have?
1. Taste buds
2. Food bolus
36
Are salivary glands paired?
Yes
37
What are the 3 glands in the oral cavity?
1. Parotid
2. Submandibular
3. Sub lingual
38
What are the properties of the parotid gland?
1. 25% secretion
2. Serous
3. Amylase
39
What are the properties of the sublingual gland?
1. 5% secretion
2. Mucous
3. Lingual lipase
40
What are the properties of the submanddibular gland?
1. 70% secretion
2. Mixed lysozyme and lactoperoxidase
41
What is the property of the lamina propria?
It's a connective tissue core that contains
1. Collagen fibers
2.elastic fibers
3. Reticular fibers
4. Connective tissue cells like fibroblasts
42
What is the function of the muscularis mucosa?
To reduce diameter of GIT
43
What is the serosa?
Connective tissue layer of the GIT to hold everything in place
44
Where are goblet cells found?
Anywhere where mucus is required
1. Bronchi
2. GIT
45
what are the 3 sections of the pharynx divided into?
1. nasopharynx
2.oropharynx
3. hypopharynx/laryngopharynx
46
What area covers the nasopharynx?
everything above the soft palate
47
what are covers the oropharynx?
between the soft palate and the tip of the epiglottis
48
what area covers the hypopharyn/laryngopharynx?
from tip of epiglottis and below (not traches)
49
what is the role of the pharynx and oesophagus in the GIT?
it is a conduit for food and air (no digestion)
50
what does the parynx open into?
it splits to:
1. oesophagus (digestion)
2. trachea (breathing)
51
are respiratory passages open or closed during swallowing?
closed
52
what does patent mean?
ability to breathe
53
how is the pharynx kept patent?
the hyoid bone
54
what happens during swallowing?
the trachea moves upwards and the epiglottis closes the aditus to the larynx
55
which groups are at risk of reduced aditus function?
very old and young
56
which area of muscle in the oespophagus is voluntary and involuntary?
1. proximal is voluntary
2. distal is involuntary
57
how many liters can the stomach hold?
1.5-2.5L
58
where is the stomach located?
in the upper left abdomen
59
Where is the pancreas?
In the c shaped cavity below the duodenum
60
What is the anatomy of the liver?
1. About 2kg
2. Has a right, left, caudate and quadrate lobe
3. Gall bladder and bile duct
4. Aorta and vena cava
5. Portal vein
6. Hepatic artery
61
What is the job of the spleen?
Filtration for blood. It removes; old, malformed and damaged RBC
62
Is the spleen a part of the lymphatic system?
Yes
63
How is the spleen a part of the lymphatic system?
works to keep body fluid levels in balance and to defend the body against infections. It is made up of a network of lymphatic vessels that carry lymph — a clear, watery fluid that contains proteins, salts, and other substances — throughout the body.
64
What does the pancreas open to?
It opens to the bile duct of the gall bladder
65
What is the purpose of the pancreas?
To release pancreatic enzymes and bile to enable chemical digestion
66
What does it mean when the pancreas is a mixed gland?
1. Endocrine function: substance secreted within the blood stream
2. Exocrine function: pancreatic juice secretion into the gut, specific to GIT
67
What are the 3 parts of the small intestine?
1. Duodenum
2. Jejunum
3. Ileum
68
What is the purpose of the small intestine?
1. Break down food
2. Aborb nutrients
3. Remove waste
69
How does chyme move through the small instestine?
Via peristalsis
70
What is Migrating Myoelectric Complex?
It the movement of chyme from 2 points of the SI via contraction of smooth muscle due to AP firing, multiple times, in the rhythmical fashion
71
How is perstalsis initiated in the SI?
By a hormone called motilin that is released during fasting phase
72
What are Peyer's Patches?
A group of lymphoid molecules found in the ileum and act as a bacterial defence of the small intestine
73
What state is chyme when it reaches the ileum?
Fecal matter
74
Describe the large intestine
A sack like structure with a longitudinal muscle coat that causes haustra (pockets) to form
75
What is the primary function of the large intestine?
Reabsorption of water
76
Why doesn't the large intestine absorb nutrients?
Fecal matter present, high change of absorbing something dangerous, like amonia
77
What is the purpose of the rectum and anus?
A reservior
78
Where does the rectum begin?
At the end of the large intestine
79
What are anal columns?
Columnar like structures which have blood vessels deep to them.
Hemmeroids
80
What is the anus?
The opening at the end of the digestive tract
81
What body parts are in the upper GIT?
1. Mouth
2. Pharynx
3. Oesophagus
4. Stomach
82
What body parts are in the lower GIT?
1. Small intestine
2. Large intestine
3. Rectum
4. Anus
83
Where is the boundary for the upper and lowe GIT?
The duodenum to the spleen
84
What is the ligament of Trietz?
A fold of peritoneal between the duodenum and near the spleen that's held up against gravity
85
What is luminal basal movement?
The movement of molecules from the lumen to the base of the epithelial cells
86
What is ingestion?
The process of food being taken into the alimentary canal, chewing and swallowing
87
What is propulsion?
Movement of food through the GIT
88
What is segmentation?
Mainly done in the small intestine,localized contractions of the smoothe muscle in the GIT causes chyme to break apart into smaller bundles
89
What are the 4 papillae on the tongue?
1. Filiform
2. Fungiform
3. Foliate
4. Circumvallate
90
Where is filiform papillae found?
On most of the caudal tongue, hair like in structure
91
Where is the fungiform found?
On the caudal part of the tongue, small knobs in structure
92
Where is the foliate papillae found?
Oh the distal and side of the tongue, leaf like in structure
93
Where is the circumvillate found?
At the back of the tongue across the superior of the tongue, large knobs
94
What is the purpose of the tongue?
Taste via the CNS
95
What areas of the tongue detect which flavours?
Tip: sweet/salty
Back: bitter
Side: greasy
96
How is stimulus carried from the tongue to the brain?
3 Cranial nerves
97
What are the 3 Cranial nerves that carries taste to the brain?
#7: facial
#9: glossopharyngeal
#10: vagus
98
Where for nerves 7/9/10 synapse?
Cerebral Cortex to gustatory cortex
99
What does the gustatory cortex experience?
Flavour, sits close to amygdala
100
What 2 mechanisms control salivary release?
1. Local: pressure and chemoreceptors
2. Central: sight/smell induces a positive feedback loop to create saliva
101
What is the pathway of saliva production?
1. Local/central stimulus
2. Synapse in medulla
3. ANS activates salivary gland
4. Increase salivary secretion
102
What is the pathway for dry mouth?
1. SNS activates a cascade effect
2. beta adronergic receptors activates phosphokinase A (PKA) enzyme
3. PKA mobilizes Ca2+ to move mucus filled vacuoles to basal of cell
4. Vacuoles come into contact with membrane and exocytoses into the oral cavity.
5. This causes dry mouth
103
Explain the pathway to create watery saliva
1. PNS activates noradrenaline (NA) release and Acetyl Choline release (ACh)
2. NA activates the alpha adronergic receptors and ACh activates the muscarinic receptors (M³)
3. They both activate the inositol triphospate (IP³) and diacylglycerol (DAG) pathway to create a dual action.
4a. Ca2+ increases, causing increased mucus production
4b. Phosphokinase C (PKC) is activated
5a. PKC causes Cl- to move to lumen of acini in salivary gland
5b. Cl- cotransports into acini with Na+ and K+
6. Na+ pushed out of cell to avoid lysing, H²O follows
7. Watery saliva!
104
What state is saliva in when secreted into the lumen of the acini?
Isotonic
105
What are the 2 sphincters of the oesophagus?
1. Upper oesophegeal
2. Lower oesophegeal
106
What is the function of the upper oesophegeal sphincter?
1. Voluntary control
2. Closed at rest
3. Opens when food passes through
107
What is the properties of the lower oesophegeal sphincter?
1. Involuntary control
2. Closed at rest
3. Opens when bolus is moving to the stomach
4. Within the abdominal cavity
108
Where are parietal cells found?
In the funds and body of the stomach
109
What does a parietal cell secrete?
1. Intrinsic Factor - B12 secretion
2. Hydrochloric Acid
110
Where are Chief cells found and what is their purpose?
1. Fundus of the stomach
2. Pepsin secretion
111
What cells are found in the body of the stomach?
1. Parietal cell
2. Chief cell
3. APUD
4. G-cell
5. Mucus secreting cell
6. ECL
112
How is pepsin created in the stomach?
HCl activates pepsinogen rendering the stomach sterile against ingested pathogens
113
What are the physiological phases in the stomach during mastication?
1. Cephalic: food in mouth, stomach getting ready for digestion
2. Gastric: food digested in stomach
3. Intestinal: negative feedback loop when full to reduce acid secretion.
114
What triggers an action potential in the stomach?
Food entering the stomach
115
What do the action potentials do in the stomach?
Create contractions and migrating myoelectric complexes
116
What are migrating myoelectric complexes?
Action potentials that travel the whole length of the intestine
117
How does the bolus move through the intestine?
Through mixing peristaltic waves that squeeze and segment the bolus to further digestion
118
What is gastric emptying?
When the sphincter of the duodenum opens to move the bolus into the intestine
119
What is retrograde peristalsis?
Vomiting
120
How is vomiting induced?
Chemoreceptor trigger zone activated, sends signals via the solitary tract to the cerebral cortex which contacts the abdominal muscles to increase pressure
121
List the gastric secretions
HCl
Pepsin
Prostaglandin
Mucus
122
How are ulcers formed?
Reduced prostaglandins
123
List the molecular transfer in parietal cells
1. CO² from blood stream into cell, metabolises with H²O to create H²CO³ (carbonic acid).
2. H²CO³ quickly dissociates into HCO³ and H+ due to carbonic anhydrase
3. HCO³ moves into the blood stream via an antiporter with Cl- this creates an alkaline tide in the blood.
4. Cl- moves into the stomach lumen via the Cl- channel
5. An ATP pathway moves K+ in and out of the cell via diffusion and a proton pump respectively, this allows the H+ to move into the lumen of the cell.
6. Cl- and K+ bind to create HCl
124
Where does the CO² come from in the body?
1. Respiratory
2. Cellular metabolism
125
How does medication work to enable ulcer recovery?
It blocks the proton pump
126
What are the 4 receptors that affect gastric acid secretion?
1. Cholecytokine B (CCK)
2. Somatostatin Receptor (SSR)
3. Muscarinic (M³)
4. Histaminergic Receptor (H²-R)
127
which 3 receptors in the stomach increase gastric acid secretion?
1. Cholecytokine B (CCK)
2. Muscarinic (M³)
3. Histaminergic Receptor (H²-R)
128
which receptor in the stomach decreases gastric acid secretion?
Somatostatin Receptor (SSR)
129
which receptor is normally blocked to help the stomach achieve homesostais?
Histaminergic Receptor (H²-R)
130
what are the 3 parts of the small intestine?
1. duodenum: 25cm, chyme mixes with pancreatic juices and bile
2. Jejunum:4m, absorption of Amino Acids, lipids,CHOs, Fe and Ca2+
3. illeum: 2.5m, absorption of B12 and bile salt
131
what is the primary purpose of the small intestine?
absorption
132
what is chyme?
compressed food mixed with pepsin and salivary amylase
133
what is secretin?
a hormone produced in the S-cells of the duodenum, creating pancreatic bicarbonate, to cause contraction of billary ducts in the liver.
134
what is the purpose of secretin release?
This causes bile bile from the gall bladder and duct system move towards the duodenum, which makes food alkaline and starts digesting fats
135
what does bile acid enable?
emulsifies fats
136
does the vagus nerve have stimulation of the gall bladder?
yes, a weak one
137
what does cholecystokinin do?
1. contracts the gall bladder
2. relaxes the sphincter of Oddi
138
where does cholecystokinin come from?
the bloodstream
139
is bile secretion a postive or negative feedback loop?
postivie
140
describe the molecular pathway of pancreatic acinar cells?
1. CO² from blood stream into cell, metabolises with H²O to create H²CO³ (carbonic acid).
2. H²CO³ quickly dissociates into HCO³ and H+ due to carbonic anhydrase
3. HCO³ moves into the cell via cotransport with Na+
4. Na+ also moves into the cell via an antiporter to move H+ into the blood stream
5. an ATPase pathway recycles K+ between the cell and the bloodstream to move Na+ into the cell, this causes ion flux within the cell
6. Na+ lastly, moves into the lumen via paracellular transport from the bloodstream "leaky junction"
7. HCO3- from cotransport and dissociation; moves into the lumen via an antiporter with Cl- moving into the cell
8. Cl- is recycled back into the lumen by cotranport via the CFTR channel with HCO3-
141
how is pancreatic secretion controlled?
1. 10th Cranial Nerve (Vagus)
2. Cholecytokine B (CCK)
142
what is the primary function of the large intestine?
1. water absorption
2. micrbiome maintenance
3. to reduce waste os water and electrolytes
143
how much material is absorbed via the large intesting, and where?
6L/d mostly from the first half of the large intestine (ascending and 2/3 transverse colon)
144
describe the molecular pathway of the large intestine
1. CO² from blood stream into cell, metabolises with H²O to create H²CO³ (carbonic acid).
2. H²CO³ quickly dissociates into HCO³ and H+ due to carbonic anhydrase
3. HCO3 moves into the lumen via an antiporter with Cl- moving into the bloodstream
4. Cl- diffuses out of the cell, into the bloodstream via diffusion
5. H+ moves into the lumen via and antiporter with Na+, which moves into the cell
6. an active antiporter recycles K+ between the cell and the bloodstream to move Na+ out of the cell, this causes ion flux within the cell
145
why is both H+ and HCO3- moved int othe lumen of the large intestine?
to not have acidic poo
146
why is it bad to be chronically constipated?
it causes over absoprtion of toxic substances into the bloodstream (NH4) which can cause death
147
give examples of macronutients
1. carbohydrates
2. fats
3. proteins
148
of the macronnutrients, which is the main source of energy?
carbohydrates
149
give examples of sugars within the body
1. monosaccarides
2. glucose
3. fructose
4. galactose
150
give an example of disaccarides
1. sucrose (glucose + fructose)
2. lactose (galactose + glucose) reducing sugards
3. Maltose (2x glucose) - reducng sugars
151
what is a disaccaride?
when two monosaccharides are joined by glycosidic linkage. Like monosaccharides, disaccharides are simple sugars soluble in water.
152
what is a reducing sugar?
any sugar that is capable of acting as a reducing agent. (donates electrons)
153
what is starch?
complex (amylose + amylopectin)
154
what is glycogen?
stored glucose found in muscles (branched polysaccarides)
155
describe carbohydate absorption
1. glucose enters the bloodstream andcomes into contact with the brush border enzymes
2. the enzymes break down glucose to easier absorption
3. the socium-glucose-transporter (SGLT) receptor cotransports Na+ and glucose into the cell from the small intestine
4. a proton pump at the basal of the cell causes an ion flux due to the movement of K+ and Na+ into and out of the cell, water also follows Na+
5. the ion flux causes the glucose to move to the basal of the cell where is moves into the interstitial fluid via the GLUT-2 receptor
6. the glucose then moved from the interstitial fluid, into the capillaries and into the bloodstream
156
describe the process of fat absoption
1. large molecules are emusified by bile salt into lipid emulsion
2. lipid emulsion is further broken down by pancreatic lipase into monoglyceride and free fatty acids
3. Bile salts breaks down and compacts these into micelles
4. As micelle is a lipid is diffuses into the cell of the small intestine
5. micelle dissoves in the cell and releases the MG and FFA, which is carried by a protein to the ER
6. the ER forms the trigylceride and sends it to the Golgi apparatus, where it is placed in a vesicle of chylomicrons and exocytosed out of the cell into the interstitial fluid.
7. once in the fluid they are pushed into the lympthatic vessel
157
describe protein obsorption
1. proteins are broken don into amino acids which are then co-transported into the small intestine cell with Na+ fro mthe lume
2. a Na+ and H+ antiporter moves H+ into the lumen and Na+ into the cell, to enable more water to move into the cell
3. a proton pump at the basal of the cell causes an ion flux due to the movement of K+ and Na+ into and out of the cell, water also follows Na+
4. the ion flux causes the amino acid to move to the basal of the cell andinto the blood stream via simple diffusion
158
how much iron do we absorb everyday?
~20mg, but only use ~2mg
159
what are the 2 forms and 3 groups of iron?
1. Heme and ferrous iron (Fe2+): aborbs well
2. non heme iron (Fe3+): not absorbed well
160
where is non heme iron found?
in plant based material like spinach
161
what element doesn't allow Fe2+ absorption?
Ca2+
162
describe the process of iron absorption
1. non heme iron contacts the bursh border and is carried into the cell by Heme carrier protein 1 and divalent metal transporter 1
2. some iron bonds with the protein called proapoferotin and is stored in the cell
3. some iron moves to basal of cell where the protein ferroportin moves it to the bloodstream
4. once in the bloodstream a protein called prottransferrin joins with the iron to become transferrin
5. transferrin moves to where it's requiireed in the body
163
what hormone controls iron release into the body?
Hepcidin
164
how is iron lost in the body?
1. bleeding
2. periods (cellular sloughing)
165
is the defecation reflex concious or unconcious?
both
166
describe the process of defecation
1. feces reaches sygmoid colon and rectum
2. rectum stretches due to a local reflex (no to brain, concious)
3. the internal sphincter unconciously relaxes due to pressure
4. external sphincter conciously relaxes when you are ready to defecate
167
what would happen to the defecation reflex if you had a spinal cord injury?
you wouldn't be able to control the defectaion reflex
168
what % of CO does the kidney use?
20%
169
what are the functions of the kidney?
1. homeostasis
2. waste removal (ammonia, urea, uric acid, creatinine)
3. formation of urine
4. endocrine function (renin and erthropoietin (RBC genesis)
5. osmolarity regulation
6. acid/base balance
7. Ca2+ homeostasis
8. detoxification
170
describe the anatomy of the kidneys
2 of them, L and R
attached to a urter, which is attached to a urinary bladder
urethra is attached to the urinary bladder
171
what is the pathway of urine in the kidney?
1. nephron creates urine and drains it into the collecting duct
2. from the collecting duct the urine moves into the papillary duct (in the pyramid)
3. from the papillary duct it moves into the minor calyx
4. then to the major calyx
5. then to the renal pelvis
6. then to the ureter
7. to the bladder
8. to the urethra
9. out of the body
172
what is an extension of the renal cortex?
renal column
173
how is the structure of the ranal medulla described?
pyramid, with an apex and a base
174
where is the proximal and distal convoluted tutble in relation to the kidney?
in the renal cortex
175
where is the straight tutbules, loop of henle and collecting duct in relation to the kidney?
in the medulla
176
what happens in the Bowman's capsule?
Glomerulus capillaries are stuffed in there so the pressure difference forces out filtrate from the capillaries into the nephron
177
what is thr glomerulus?
a bundle of capillaries within the Bowman's capsule
178
explain the flow of filtrate through a nephron
1. blood flows into glomerulus from afferent capillaries
2. filtrate leaves the capillaries due to pressure into the Bowman's Capsule
3. filtrate moves into the proximal convoluted tubule where molecules and nutrients leave the nephron and move into the kidney for absorption
4. some glucose left in tubules as it is osmotically active so water will move into the Loop of Henle
5. H+ and NH3 moves into tubules and into the descending loop of henle, which is permeable to H2O, not NaCl, so filtrate will lose H2O, concentrating the filtrate and raising the osmolarity from 300osmol to max 1200osmol
6. the base of the loop of henle is at 1200osmol, this creates an isotonic space, so no net movemnt of molecules ocurs here
7. ascending loop of henle is permeable to NaCl, so NaCl will move into the kidney, reducing the osmolarty back to 300osmol
8. within the distal convoluted tubule HCO3-, NaCl and H2O is absorbed into the kidney, HCO3- to keep the pH balance, K+ and H+ is taken intothe nephron
9. within the outer medulla ADH will activate aquaporins on the collecting duct to absorb more water into the body to reduce dehyration
179
does the kidney have it's own nerve supply?
Yes
180
is the kidney innervated by the PNS or SNS?
both, has control over RAAS (blood pressure)
181
what is the network of capillared called within the kidneys and around the nephrons?
Counter current exchange
182
does the ureter have it's own blood supply?
Yes
183
is the ureter innervated by the PNS or SNS ?
both
184
which artery supplies blood to the ureter?
Renal artery, it partners with regional vessels along the way
185
what are the 3 areas of constriction in the ureter?
1. pelviuritary junction (PUJ)
2. iliac blood vessel crossover
3. vesicle uriteric junction (meets bladder)
186
where are kidneystones most likely to be found?
in the areas of contriction within the ureter
187
how much urine does the bladder hold?
~250-300ml
188
what happens to the bladder lining when empty?
it folds into itself to create rugae
189
what is rugae?
a series of ridges due to the folding of an organ, e.g. in stomach and bladder
190
what is the triangular area of a bladder that doesn't form rugae?
the trigone of the bladder
191
is the bladder controlled by the SNS or PNS?
both
192
which nerves acivate the PNS of the bladder?
Nervi Erigentes (S2-4)
193
explain the control of urination
1. bladder fills a signal is sent to lower spinal cord to activate a local reflex
2. local reflex arch synpases with interneurons, efferent neurons in symp. ganglia to innervate the bladder wall.
3. detrusor muscles in the wall and sphincters of the bladder are innervated to contract and relax respectively.
4. when holding bladder (voluntary) afferent signals sent to pons control mechanism to hold pee in
5. due to involuntary control from local reflex has relaxed musclesand sphincters some urine is in the urethra, which activates the sensation of needing to pee.
194
is urination a local or central reflex?
it is a local reflex, with central control, this gives the sensation of needing to pee, without wetting yourself
195
how much body fluid does a body generall hold?
~30-40L
196
what is the plasma osmolality generally held at?
275-295mOsm/kg
197
what ratio is plasma within the ECF and ICF in the human body?
2:1
198
within the extra cellular fluid, how much plasma is within the interstitial fluid?
about 3/4
199
what happens to fluid particles when temperature increases?
they become more active
200
what is a uniport carrier?
where 1 cell is moved into or out of a cell
201
what is a symport carrier?
where 2 particles move in the same direction
201
what is an antiport carrier?
when 2 particles move in opposite directions
202
Describe the counter current multiplier system
When the proximal convoluted tubule filtration moves into the loops of Henle. Here the osmolality increases from 300 to 1200 osmol due to absorption of water into the kidney. It then drop back to 300ml in the asce ding loop of henle because Na and Cl move out of it and into the kidney. This cases the capillaries within the loop of henle space to fluctuate in pressure
This Flux is the counter current system
203
What happens to the pituitary gland when there's too much salt in the body?
It release ADH, which encourages the collecting duct to absorb more water, retaining it, instead of peeing it out.
204
Is urine regulation controlled by a local or central mechanism?
Central: the pituitary gland
205
What does ADH do to the collecting tubules of nephrons?
It opens more aqaporins on the collecting duct to absorb more water back into the body
206
What happens to urine if it's hypotonic?
Sodium is reabosrbed to the body to make it isotonic
207
What happend to urine if it's hypertonic?
More water is reabosrbed back into the body through aquaporins, to create an isotonic balance
208
What is Glomerular Filtration Rate? (GFR)
How the function of the kidney is described.
The amount of blood flowing through the glomerulia at and given time.
The flow of plasma from glomerulus to bowmans space over a specified period of time
209
What could happen if the GFR drops?
Death
210
What factors influence GFR?
1. Renal flow and perfusion pressure (RAAS)
2. Surface area (damage=more toxins)
3. Hydrostatic pressure: fluid compartment (water)
211
What is a normal Renal Blood Flow (RBF)
About 1200ml/minute
212
What is total renal vascular resistance is RBF dependent upon?
1. SNS*
2. Adrenaline*
3. Noradrenaline*
4. Endothelin
5. Renin*
6. Angiotensin 2*
7. Prostaglandin
8. Glucose and protein increase (sometimes)
213
What is the equation to find pressure in Ren artery?
Pressure in renal artery - pressure in renal vein
214
What is urinary secretion dependent upon?
GFR: reduced GFR = Reduced secretion of toxins, so more urea will build in the body
215
How else can we remove urea fro mthe vody?
Sweat, causing a crustiness on the skin
216
What do kidneys excrete to maintain homeostasis?
Cations and anions
217
What molecules are reabsorbed from the nephron tubules to maintain homeostasis?
Na+, K+, Ca²+,PO⁴-, Mg²+, Cl-, HCO³-
218
How do molecules move from glomerulus to bowmans space?
Hydrostatic pressure
219
How is the counter current multiplier triggered?
By sensors in the heart and blood vessels
220
What does the counter current multiplier prevent?
Large quantities of urine being diluted daily
221
What is the name of the blood vessels inside the loop of henle?
Vasa recta
222
What happens in acidosis in the kidney?
More HCO³- is reaborbed, collecting ducts secrete more H+, which creates more bicarbonate and NH³, so a buffer is formed
223
What happens in alkalosis?
Kidney excretes more HCO³- and reduces secretion of H+, more NH³ is secreted
224
How can the body become imbalanced regarding acidosis or alkalosis?
Either metabolically or respiratory
225
What 2 organs work together to create and acid base balance?
Kidneys and lungs
226
What can increase acidosis?
1. Excercise (breathing in mor CO²)
2. Diabetic keto acidosis: too much glucose, not enough insulin to control it, which breaks down fats faster and releases ketones, which are acidic
227
What can cause alkalosis?
Vomiting: H+ ions are lost
228
How does RAAS help control the acid base balance?
It increases and decreases blood pressure to facilitate exchange of ions accordingly
229
Describe the RAAS
1. Renin Angiotensin Aldosterone System
2. Increase SNS, decrease pressure, Na+ delivery to tubules
3. Renin activates ans reacts to angiotensinogen that has been released from the liver
4. This converts to angiotensin 1, which is converted into angiotensin 2 by the angiotensin converting enzyme (ACE) from the lungs.
5. Angiotensin 2 will increase vascular resistance, so the blood pressure increases, so mor Na+ will flow through nephrons, achieving homeostasis
230
What does aldosterone do to NaCl in the collecting duct?
Absorbs NaCl to make urine less concentrated
231
What is Erythropoietin (EPO)?
A hormone mainly created by the kidney and a little bit from the liver
232
What is the purpose of erythropoietin?
Produce red blood cells
233
How does erthropoietin keep rbc and oxygen stable?
Through a dynamic feedback loop
234
Does increated erythropoietin increase or decrease O²?
Increase
235
Does erythropoietin move to bone marrow?
Yes
236
Is erythroproeitin active for a short or long time?
Long time
237
What areas of the body does erythroproetin affect?
1. Endothelium
2. Heart
3. Muscle
4. White fat
5. Brain
6. Bone marrow
238
Is erythropoietin inverse to O²?
Yes
239
Where is vit D found in the body?
1. Liver
2. Kidney
3. Skin
4. Immune cells
5. Parathyroid gland
6. Intestinal epithelium
7. Prostate
8. Breast
240
Describe the vitamin D pathway
1a. Food
1b.From sunlight on the skin via UVB.
2. Converts to 7 dehydrocholesterol
3. Converts to previtamin D
4. Converts to Vitam D, which is done in the liver
5. Metabolises into 25 hydroxy vitamin D
6. Converts to 250 HD³ in the kidney
241
What is the main enzyme to produce 125 hihydroxy vit D?
Renal 1 hydroxylase
242
What area of the body produce renal 1 hydroxylase?
Parathyroid hormone FGF23, calcium and phosphate
243
What are cytokines dependent on for vit D?
The regulation of extra renal hydroxylase
244
How is vitamin D carried in the blood?
1. Vitamin D-binding-protein
2. Albumin
245
What can vitamin D protect you from?
1. Cancer
2. Blood pressure
3. Heart disease
4. Immunitilogical disorders
246
How is calcium and phosphorus regulated in the body?
By 125 dihydroxy from the kidney and parathyroid hormone (PTH)
247
How is calcium and phosphorus regulated in the body?
By 125 dihydroxy from the kidney and parathyroid hormone
248
Where is the major site of synthesis for 1 alpha 25 dihydroxy vitamin D?
Kidney
249
How is 25 hydroxy vitamin D 1 alpha regulated?
1. Parathyroid hormone
2. Fibroblast growth factor
3. 23 FGF
4. Inorganic phosphorous
250
Does the kidney have a receptor for 1 alpha dihydroxy vitamin D?
Yes
251
Is Ca²+ an intracellular or extracellular messenger?
Both
252
What's percentages is calcium bound in to move around the body?
40% protein bound
10% in an anion complex like citrate and sulphate
50% freeform
253
Why is Ca²+ tightly regulated?
Because any discrepancy can cause significant damage to the body as it influences so much
254
Where is 99% of calcium reabsorbed?
In the renal tubules of the nephron in the kidneys
255
What 3 tissues regulate plasma phosphate regulation?
1. Bone tissue
2. Intestinal tissue
3. Kidneys
256
What are the major factors of regulation for plasma phosphate?
1. Parathyroid hormone
2. Vitamin D and fibrogrowth factor 23 (FGF 23)
257
Describe the plasma phosphate regulation
1. Increase of plasma phosphate causes a release of: PTH and FGF23
2. Increase of PTH increases calcitriol synthesis and phosphate excretion
3. FGF23 causes a reduction of calcitriol and increases phosphate excretion
258
How does calcitriol affect plasma phosphate levels?
It stimulates Ca²+ ans PO⁴(³-) uptake in GIT ans reabsoption in renal
259
How does the parathyroid hormone regulate plasma phosphate?
Stimulates the rapid transfer of Ca²+ and PO⁴(³-) from bone to increase PO⁴(³-) excretion and reabosrbtion of Ca²+
260
How does FGF23 regulate plasma phosphate?
Increases the excretion of PO⁴(³-) and reabsorption of Ca²+
