Week 14 - Renal/LE Flashcards
1
Q
What are the components of internal K balance?
Of external K balance?
A
internal: intracellular vs extracellular pools
external: intake vs excretion
2
Q
What things can increase K shifting into the cell?
How is this accomplished?
A
- insulin and B2 agonists
- increases the activity of the Na/K ATPase
3
Q
What are the ways to affect internal K balance?
A
- insulin and B2 agonists bring K into the cell
2. acid/base status, where acidemia kicks K out (and alkalemia sucks K in)
4
Q
Where does regulation of external K balance mainly occur?
A
in the kidney
5
Q
Where can you lose K to, externally?
A
- kidney
- GI tract
- skin
6
Q
Describe the proximal tubule’s overall role in K balance.
A
it participates in a significant amount of K reabsorption, but is not a site for major regulation
7
Q
Describe the TAL’s overall role in K balance.
A
it participates in a significant amount of K reabsorption, but is not a site for major regulation
8
Q
Describe the distal neprhon’s overall role in K balance.
A
- it secretes K variably, depending upon a lot of factors including the size load
- it is a major site for K regulation
9
Q
Where does K secretion occur?
How?
A
- the principal cells of the late distal tubule and collecting duct
- K channel in the apical membrane
10
Q
What maintains the high intracellular K concentration in the principal cells?
A
the Na/K ATPase
11
Q
Of the 3, where is K concentration the highest:
tubular lumen, inside the principal cell, or ECF?
A
inside the principal cell (thanks to the Na/K ATPase)
12
Q
What is the negative lumen potential in the principal cell generated by?
A
ENaC
13
Q
What is the net movement of K in the principal cells?
What things allow for that?
A
- K secretion via K channels
- electrochemical gradient made by ENaC and the Na/K ATPase
14
Q
What can lower the drive for K secretion?
A
- intercellular K concentration decreases
- lumen K concentration increases
- lumen potential becomes less negative
15
Q
What is one of the most important regulators of K secretion?
A
aldosterone
16
Q
What are the methods in which aldosterone affects K secretion?
A
- aldosterone increases the activity of the Na/K ATPase, increasing intracellular K
- increase the number of ENaC channels, causing increased reabsorption of Na, leading to an increase in the negative lumen potential
- increases the number of K channels in the apical membrane of the principal cell
17
Q
Why does tubular fluid flow rate have a large effect on K secretion?
A
- if low/no blood flow, the K equilibrates and K secretion stops
- if fast flow, the secreted K is swept away and the gradient remains strong, promoting K secretion
18
Q
What things increase K secretion?
A
- aldosterone
- increased dietary K
- increased Na delivery
- increased flow rate
- loop diuretics
- thiazide diuretics
- alkalosis
19
Q
What things decrease K secretion?
A
- decreased dietary K
- decreased flow rate
- K-sparing diuretics
- acidosis
20
Q
In regards to ADH, what happens when there is excess free water?
A
this means that serum osmolarity is low, inhibiting ADH release, causing the kidney to produce dilute urine and dump free water (and vice versa for low free water)
21
Q
Where is the primary target for ADH action in the kidney?
A
the principal cell of the collecting duct
22
Q
Describe the principal cell when there is no ADH, theoretically.
A
collecting duct will be impermeable to water
23
Q
Describe the principal cell when there is ADH.
A
ADH stimulates V2 receptors to insert acquaporin2 channels into the apical membrane, making the collecting duct permeable to water
24
Q
Is ADH an all-or-none phenomenon?
A
no, the more ADH is around the higher the water permeability will be (in varying degrees)
25
How does ADH help to make a concentrated urine?
- causes aquaporin 2 insertion in principal cells (saving free water from being lost in urine)
- stimulates NKCC2 in TAL (takes more stuff out of the urine into the medulla, makes hyperosmolar inner medulla)
- increases reabsorption of urea from the collecting duct into inner medulla (makes hyperosmolar inner medulla)
26
Why is Na primarily regulated?
for ECF volume
27
Why is free water primarily regulated?
for osmolarity (or Na concentration)
28
What is the kidney's role in acid/base balance?
1. bicarb reabsorption
| 2. acid excretion/new bicarb production
29
What processes are involved in acid excretion/new bicarb production?
- titratable acids
| - ammonium generation
30
Where does bicarbonate reabsorption occur?
| How?
- in the proximal tubule (indirect process)
1. Na/H antiporter secretes H into lumen (+ by ang II), which associates with bicarb to make carbonic acid
2. carbonic anhydrase makes CO2 and water, pulling more H into the reaction by removing the acid
3. CO2 and water move into the cell
4. a different carbonic anhydrase pushes them back into carbonic anhydrase, which immediately dissociates into bicarb and H
5. bicarb pumped out of basolateral membrane where it diffuses into the blood stream
6. H is recycled back to the lumen via Na/H antiporter to bind with another bicarb
31
What is the NET in bicarb reabsorption?
- movement of bicarb from the lumen to the bloodstream
- no NET acid excretion
- no generation of new bicarb
32
What structure can reclaim essentially all of the filtered bicarb?
the proximal tubule
33
What stimulates the activity of the Na/H antiporter in the proximal tubule?
In the collecting duct?
- PT: angiotensin II
| - CD: aldosterone
34
What processes result in net acid excretion?
| Where does each occur?
- titratable acids, in the proximal tubule
| - ammonium generation, in the proximal tubule
35
Describe the process of titratable acids.
1. carbonic anhydrase makes carbonic acid from water and CO2 in the proximal tubule cells
2. carbonic acid immediately dissociates into H and bicarb
3. H ions are pumped into the lumen via the Na/H antiporter
4. the H in the lumen is buffered by the phosphate that was previously filtered
5. the bicarb made uses the bicarb/Na symporter to enter the blood, acting as a buffer there
36
Which process is more important- titratable acids or ammonium generation?
Why?
Ammonium generation, because it is an inducible process where more ammonium can be generated if more acid needs excreted. The phosphate is limited in amount to what was filtered
37
Describe the process of ammonium generation.
1. glutamine is broken down into ammonium and a-ketoglutarate in proximal tubule cells
2. a-ketoglutarate is converted to bicarb, which is pumped into the blood
3. ammonium is pumped into the tubular lumen (the Na/H antiporter doubles as a Na/NH4 antiporter)
4. pH converts ammonium to ammonia in the tubular fluid
38
Describe the process of ammonium excretion.
1. water and CO2 make carbonic acid using carbonic anhydrase
2. carbonic acid dissociates into H and bicarb
3. bicarb is transported into the blood
4. H pumped out via the H-ATPase
5. ammonia combines with H to make ammonium, which is excreted
39
Where does ammonium generation occur?
| Ammonium excretion?
- generation: mostly in the proximal tubule
| - excretion: in the intercalated cells of the collecting duct
40
What simulates the H-ATPase activity?
| What process is that transporter important for?
- aldosterone
| - ammonium excretion
41
What is the normal fractional excretion of K?
10-20%
42
Why do thiazide and loop diuretics cause K wasting?
they inhibit the Na reabsorption upstream of the collecting duct, causing high Na delivery to the collecting duct, which drives further K secretion by the principal cells
43
What are the pH limits compatible with life?
6.8 to 7.8
44
What is the net effect of ammonium generation/excretion?
- excretion of acid in urine
| - generation of new bicarb to replenish what was consumed buffering metabolic acids in the ECF
45
Why can hyperaldosteronism be associated with metabolic alkalosis?
Aldosterone stimulates the activity of the H ATPase in the distal collecting duct. This pushes more new bicarb into the bloodstream.
46
What is likely your K state if you have acidosis?
hyperkalemia (with acidosis, cells buffer about half of H+ by taking it into the cells -- push K+ into ECF for electroneutrality)
if low on total K (urinary/GI losses) and in acidosis, will have artificially normal K in ECF but when acidosis is corrected and take up K again -- reveals low K
47
What is likely your K state if you have alkalosis?
hypokalemia (alkalosis makes you reduce H secretion, so dump more K to keep the charge balance)
48
What defines respiratory acidosis?
a PaCO2 over 45 mmHg
49
What defines respiratory alkalosis?
a PaCO2 under 35 mmHg
50
What defines metabolic acidosis?
bicarb concentration less than 22 mEq/L
51
What defines metabolic alkalosis?
bicarb concentration greater than 28 mEq/L
52
What can cause metabolic acidosis?
| What is usually present?
- excess production of acids (ketones, lactic acid, chronic renal failure)
- ingestion of fixed acids (methanol, ethylene glycol, aspirin)
- loss of bicarb (GI fluid loss from diarrhea, renal tubule acidosis)
-compensatory respiratory alkalosis: reduces arterial PCO2 and increases the pH towards normal
53
How do you resolve metabolic acidosis without treatment?
- increased renal generation of new bicarb
- increased H excretion via NH3 production
- titratable acid excretion
54
```
Metabolic acidosis:
H?
Bicarb?
Arterial PCO2?
Compensation?
```
- increased H concentration
- decreased bicarb concentration
- decreased arterial PCO2
- hyperventilation (secondary respiratory alkalosis)
55
```
Metabolic alkalosis:
H?
Bicarb?
Arterial PCO2?
Compensation?
```
- decreased H concentration
- increased bicarb concentration
- increased arterial PCO2
- hypoventilation (secondary respiratory acidosis)
56
```
Respiratory acidosis:
H?
Bicarb?
Arterial PCO2?
Compensation?
```
- increased H concentration
- increased bicarb
- increased arterial PCO2
- increased H excretion and increased bicarb generation (renal)
57
```
Respiratory alkalosis:
H?
Bicarb?
Arterial PCO2?
Compensation?
```
- decreased H concentration
- decreased bicarb
- decreased arterial PCO2
- decreased H excretion and decreased bicarb generation (renal)
58
How do you calculate the anion gap?
Na - (Cl + bicarb)
59
What is the normal anion gap?
| What does that reflect?
- between 8-16 mEq/L
| - the concentration of unmeasured anions like protein, phosphate, sulfate, and citrate
60
When metabolic acidosis is caused by a loss of bicarb, what happens to the anion gap?
there is an increase of Cl (hyperchloremic metabolic acidosis) rather than the addition of other unmeasured anions, and the anion gap is normal (b/c ECF is electroneutral at all times in regards to measured anions)
61
What are the most common causes of metabolic acidosis with an increased anion gap?
```
(MULEPAK)
Methanol ingestion
Uremia
Lactic acidosis
Ethylene glycol ingestion
Paraldehyde ingestion
Aspirin overdose
Ketoacidosis
```
62
What are the most common causes of metabolic acidosis without an increased anion gap?
```
(Could Really DeHydrate)
Carbonic anhydrase inhibitors
Renal tubular acidosis
Diarrhea
Hyperalimentation (IV feeding)
```
63
What are the most common causes of metabolic alkalosis?
- loss of gastric H from vomiting (excess bicarb in blood)
- contraction alkalosis, a net gain of bicarb by the renal system (bicarb retention occurs as a side effect of low effective circulating volume)
64
How can low effective circulating volume cause bicarb retention?
- low GFR, reducing the bicarb filtered load
| - avid proximal tubular reabsorption regardless of filtered load
65
What usually accompanies metabolic alkalosis?
compensatory respiratory acidosis, where arterial PCO2 increases to try to decrease the pH back to normal
66
How can you correct metabolic alkalosis without treatment?
- increased renal excretion of bicarb
- reduced rates of acid excretion
- reduced rates of bicarb retention
67
What physiologically causes respiratory acidosis?
inadequate alveolar ventilation that results in CO2 retention
68
What can things can cause respiratory acidosis?
- neuromuscular disorders
- airway obstruction
- narcotics that suppress breathing
69
What happens in chronic respiratory acidosis?
the renal system normalizes the pH by excreting more acid and producing more bicarb, which is added to the ECF
70
What are sensible losses?
water loss that we can measure
71
What are insensible losses?
water loss that you cannot measure
72
What physiologically causes respiratory alkalosis?
excessive alveolar ventilation, resulting in greater CO2 loss than production
73
What can cause respiratory alkalosis?
- high altitude (hypoxemia)
- pulmonary embolism (hypoxemia)
- psychogenic hyperventilation
74
What happens in chronic respiratory alkalosis?
the renal system normalizes the pH by excreting less acid and producing less "new" bicarb
75
What does 'compensation' refer to?
responses that normalize plasma pH
76
If both alkalosis and acidosis are present and the pH is acidic, what do you consider the primary disorder?
the acidosis (although both are present)
77
Explain the effects of excessive aspirin ingestion.
- aspirin uncouples os/phos, causing a primary metabolic lactic acidosis
- directly affects the respiratory centers in the meduall, causing the central chemoreceptors to be more sensitive to arterial PCO2 levels, which cause primary respiratory alkalosis
78
What does furosamide do?
Where does it act?
How does it work?
K status?
- inhibits the NKCC2
- the loop of Henle (TAL)
- decreases the electrochemical gradient, reducing Na, Ca, and Mg reabsorption
- K wasting, because lower electrochemical gradient by the time it gets to the collecting duct
79
What are the K wasting diuretics?
loop and thiazide
80
What are the anterior ligaments of the hip joint?
| Posterior ligaments?
- anterior: iliofemoral (Y shape) and pubofemoral
| - posterior: ischiofemoral
81
What is the strongest ligament in the body?
| Where is it located?
- the iliofemoral ligament
| - the anterior hip joint
82
What gives the blood supply to the femoral head and neck?
Where does it come off of?
Where are they located?
- the lateral and medial circumflex femoral arteries
- off of the profunda femoris artery
- in the intertrochanteric groove
83
What is the most common type of hip fractures?
| What is healing like, and why?
- intertrochanteric hip fractures
| - they heal better than other types because of denser bone and better blood supply
84
What is healing like for a femoral head fracture?
| Why?
- very difficult to heal
- because a fracture at the neck comprimises the blood supply from the circumflex femoral arteries, which can lead to avascular necrosis
85
Why are 75% of hip replacements performed?
hip osteoarthritis
86
How do hip dislocations commonly present?
| What is a common mechanism that would cause this?
- with the leg adducted and internally rotated
| - falls, car crashes (knee hitting dash board), etc
87
What is contained in the superficial fascia of the lower limb?
- cutaneous nerves
- superficial epigastric artery
- external pudendal artery
- great saphenous vein
- superficial inguinal lymph nodes
88
What is the IT tract made of?
it is a thickened continuation of the fascia lata
89
What is the blood supply to the posterior thigh?
only via 4 small perforating arteries (from the deep artery of the thigh) that pass through the adductor magnus
90
What is the deep artery of the thigh aka?
the profunda femoris artery
91
What is the chief blood supply to the anterior thigh?
the profunda femoris artery (off of the femoral)
92
What does the femoral artery become after leaving the anterior thigh?
the popliteal artery
93
What vein parallels the femoral artery in the thigh?
the deep vein of the thigh (aka profunda femoris vein)
94
What does the great saphenous vein drain into?
the femoral vein
95
What does the deep vein of the thigh drain into?
the femoral vein
96
Where do most lymph nodes in the leg drain into?
the superficial inguinal lymph nodes
97
Where do all of the hamstring muscles come off of?
a common head on the ischial tuberosity
98
What are the muscles of the posterior compartment of the thigh?
What are they aka?
- biceps femoris
- semitendinosus
- semimembranosus
-aka hamstrings
99
What innervates the hamstrings?
| What is the exception?
- the tibial division of the sciatic nerve
| - short head of biceps femoris: common fibular division of the sciatic nerve
100
What are the muscles in the anterior compartment of the thigh?
- iliopsoas
- quadriceps femoris
- sartorius
101
What are the components of the quadriceps femoris?
- rectus femoris
- vastus medialis
- vastus intermedius
- vastus lateralis
102
What are the muscles of the medial compartment of the thigh?
- obturator externus
- pectineus
- gracilis
- adductor longus
- adductor brevis
- adductor magnus
103
Where does the iliopsoas insert?
the lesser trochanter of the femur
104
What is the job of the muscles in the medial compartment of the thigh?
Where do these muscles live?
- adduction of the thigh (mostly)
| - in the groin
105
What are the boundaries of the femoral triangle?
- roof: fascia lata
- floor: iliopsoas and pectineus
- top: inguinal ligament
- lateral side: sartorius
- medial side: adductor longus
106
What lives inside the femoral triangle?
(NAVEL, from lateral to medial)
- femoral Nerve
- femoral Artery
- femoral Vein
- Empty space
- deep inguinal Lymph nodes
107
Why is the empty space in the femoral triangle important?
it is where femoral hernias can occur
108
What is the adductor canal aka?
| What are the openings at either end?
- subsartorial canal, or Hunter's canal
| - the apex of the femoral traingle and the adductor hiatus
109
What runs in the adductor canal?
| What continues on through the adductor hiatus and what does not?
- femoral artery and vein (continue through the adductor hiatus)
- saphenous nerve (continues on, but not through the adductor hiatus)
110
What are the boundaries of the popliteal fossa?
| What lives in there?
- semimembranosus, gastrocnemius medial and lateral heads, and the biceps femoris
- Contents: tibial nerve, common fibular nerve, popliteal artery and vein
111
Describe the knee joint capsule.
- outer layer: external fibrous layer
| - inner layer: internal synovial membrane
112
What are the collateral ligaments of the knee?
| What bone do they attach to?
- medial collateral ligament (MCL): tibia
| - lateral collateral ligament (LCL): fibula
113
Which collateral ligament is more robust and attaches to the meniscus?
the MCL
114
What are the cruciate ligaments of the knee?
- anterior cruciate ligament (ACL)
| - posterior cruciate ligament (PCL)
115
Which direction does the ACL run?
from lateral to medial
116
Where are the ACL and PCL located in relation to the internal synovial membrane?
Why is this important?
- ACL is almost completely enveloped and surrounded by synovium, and the PCL is mostly surrounded
- blood supply is very poor here, causing difficulty healing tears of these ligaments
117
Describe the medial meniscus.
| Describe the lateral meniscus.
- medial: C shaped, attached to tibia, MCL attaches to it
| - lateral: O shaped (mostly)
118
What motion frequently causes ACL tears?
| What else can easily be damaged?
- external rotation of the femur on the tibia, running and cutting sharply, landing on a straight knee
- the medial meniscus (they are attached)
119
Describe a 1st degree ligament injury.
some pain, minimal swelling, no loss of function
120
Describe a 2nd degree ligament injury.
moderate tear, pain, moderate loss of function, swelling, slight instability
121
Describe a 3rd degree ligament injury.
complete tear, pain, loss of function, severe instability
122
What is the function of the PCL?
| How can you injure it?
- prevents posterior movement of the tibia on the femur
| - falling on a flexed knee, or knee meets dashboard
123
What happens when you apply Valgus stress to the leg?
push the foot laterally from the knee
124
What happens when you apply Varus stress to the leg?
push the foot medially from the knee
125
If you apply Valgus stress to the knee, what will tear?
| Common mechanism of injury?
- MCL
| - athlete's knee hit from the outside
126
If you apply Varus stress to the knee, what will tear?
| Common mechanism of injury?
- LCL
| - opponent lands on inside of athlete's knee
127
Where does the saphenous cutaneous nerve innervate?
roughly the medial calf area
128
Where does the cutaneous portion of the deep fibular nerve innervate?
the webbing between the 1st and 2nd toes
129
What vein drains the medial part of the leg?
| Where does it drain into?
- the great saphenous vein
| - into the femoral vein
130
What vein drains the posterior part of the leg?
| Where does it drain into?
- the small saphenous vein
| - the popliteal vein
131
Where is the great saphenous vein located in relation to the malleolus?
the vein runs medial to the malleolus
132
Where is the crural fascia of the leg very tight over?
| Why is this a concern?
- the anterior and lateral compartments
| - could cause compartment syndrome
133
What muscles are in the anterior compartment of the leg?
- tibialis anterior
- extensor digitorum longus
- extensor hallucis longus
- fibularis tertius
134
What muscles are in the lateral compartment of the leg?
- fibularis longus
| - fibularis brevis
135
What muscles are in the superficial posterior compartment of the leg?
- soleus
- gastrocnemius
- plantaris
136
What muscles are in the deep posterior compartment of the leg?
- tibialis posterior
- flexor digitorum longus
- flexor hallucis longus
- popliteus
137
What does the flexor retinaculum create?
| What runs through there?
- the tarsal tunnel
| - tibial nerve, posterior tibial artery, medial plantar artery, and medial plantar nerve
138
What artery feeds the anterior compartment of the leg?
| What nerve is located in the anterior compartment?
- the anterior tibial artery
| - the deep fibular nerve
139
Outline the artery branching from external iliac down.
external iliac
femoral artery
popliteal
anterior tibial (to dorsalis pedis) and posterior tibial (to medial/lateral plantar arteries and fibular artery)
140
Once you cross the ankle, what does the anterior tibial artery become?
the dorsalis pedis artery
141
What does the deep fibular nerve innervate?
- the anterior compartment of the leg
| - the webbing between the 1st and 2nd toes
142
What is the anterior compartment of the leg aka?
the dorsiflexor (extensor) compartment
143
What nerve innervates the lateral compartment of the leg?
| What artery is in the lateral compartment?
- the superficial fibular nerve
| - there is no artery in this compartment
144
Injury to what can cause foot drop?
| How can this injury occur?
- the common fibular nerve or the deep fibular nerve
| - fracture to the proximal fibula
145
What is the posterior compartment of the leg aka?
the plantarflexor compartment
146
What nerve innervates the posterior compartments of the leg?
| What artery supplies that area?
- the tibial nerve
| - fibular and posterior tibial arteries
147
What motions does the talocrural joint allow for?
| What motions does the subtalar joint allow for?
- talocrural: plantarflexion and dorsiflexion
| - subtalar: inversion and eversion
148
What is the most commonly injured ligament in the body?
the anterior talofibular ligament
149
What are the important lateral ligaments of the ankle?
- anterior talofibular ligament
- posterior talofibular ligament
- calcaneofibular ligament
150
Biceps femoris:
Action?
Innervation?
Compartment?
-action: flexion and lateral rotation of the knee; extension of the hip (long head)
- long head: tibial division of the sciatic nerve
- short head: common fibular division of the sciatic nerve
-compartment: posterior of thigh
151
Semitendinosus:
Action?
Innervation?
Compartment?
- action: flexion and medial rotation of the knee; extension of the hip
- innervation: tibial division of the sciatic nerve
- compartment: posterior of thigh
(same as semimembransosus)
152
Semimembranosus:
Action?
Innervation?
Compartment?
- action: flexion and medial rotation of the knee; extension of the hip
- innervation: tibial division of the sciatic nerve
- compartment: posterior of thigh
(same as semitendinosus)
153
Sartorius:
Action?
Innervation?
Compartment?
- action: flexion, lateral rotation, and abduction of the hip, flexion of the knee (hackey sack)
- innervation: femoral nerve
- compartment: anterior of thigh
154
Quadriceps muscles:
Action?
Innervation?
Compartment?
- action: lateralis, medialis, and intermedius do extension of the knee; femoris does extension of the knee and flexion of the hip
- innervation: femoris, lateralis, and intermedius by the femoral nerve; medialis by the nerve to the vastus medialis (a branch of the femoral nerve)
- compartment: anterior of thigh
155
Iliopsoas:
Action?
Innervation?
Compartment?
- action: flexion of the hip
- innervation: femoral nerve
- compartment: anterior of thigh
156
What innervates the anterior compartment of the thigh?
the femoral nerve
157
Pectineus:
Action?
Innervation?
Compartment?
- action: adduction and flexion of the hip
- innervation: femoral nerve
- compartment: medial of thigh
158
Adductor longus and brevis:
Action?
Innervation?
Compartment?
- action: adduction and flexion of the hip
- innervation: obturator nerve
- compartment: medial of thigh
159
Adductor magnus:
Action?
Innervation?
Compartment?
Superior fibers:
- action: adduction and flexion of the hip
- innervation: posterior branch of the obturator nerve
Inferior fibers:
- action: adduction and extension of the hip
- innervation: tibial division of the sciatic nerve
-compartment: medial of thigh
160
Gracilis:
Action?
Innervation?
Compartment?
- action: adduction of the hip; flexion and medial rotation of the knee
- innervation: obturator nerve
- compartment: medial of thigh
161
Obturator externus:
Action?
Innervation?
Compartment?
- action: lateral rotation of the hip
- innervation: obturator nerve
- compartment: medial of thigh
162
Tibialis anterior:
Action?
Innervation?
Compartment?
- action: dorsiflexion of the ankle; inversion of the foot
- innervation: deep fibular nerve
- compartment: anterior of leg
163
Extensor hallucis longus:
Action?
Innervation?
Compartment?
- action: extension of the MTP and IP joints of the hallux; dorsiflexion of the ankle
- innervation: deep fibular nerve
- compartment: anterior of leg
164
Extensor digitorum longus:
Action?
Innervation?
Compartment?
- action: extension of MTP and IP joints of toes 2-5; dorsiflexion of the ankle
- innervation: deep fibular nerve
- compartment: anterior of leg
165
Fibularis (peroneus) tertius:
Action?
Innervation?
Compartment?
- action: eversion of the foot; dorsiflexion of the ankle
- innervation: deep fibular nerve
- compartment: anterior of leg
166
Fibularis longus and brevis:
Action?
Innervatin?
Compartment?
- action: eversion of the foot; plantarflexion of the ankle
- innervation: superficial fibular nerve
- compartment: lateral of leg
167
Gastrocnemius and Plantaris:
Action?
Innervation?
Compartment?
- action: plantarflexion of the ankle; flexion of the knee
- innervation: tibial nerve
- compartment: superficial posterior of leg
168
Soleus:
Action?
Innervation?
Compartment?
- action: plantarflexion of the ankle
- innervation: tibial nerve
- compartment: superficial posterior of leg
169
Popliteus:
Action?
Innervation?
Compartment?
- action: unlocks the fully extended knee at the beginning of flexion by laterally rotating the femur; flexion and medial rotation of the knee
- innervation: tibial nerve
- compartment: deep posterior of leg
170
Flexor hallucis longus:
Action?
Innervation?
Compartment?
- action: flexion of MTP and IP joints of the hallux; inversion of the foot; plantarflexion of the ankle
- innervation: tibial nerve
- compartment: deep posterior of leg
171
Tibialis posterior:
Action?
Innervation?
Compartment?
- action: inversion of the foot; plantarflexion of the ankle
- innervation: tibial nerve
- compartment: deep posterior of leg
172
Flexor digitorum longus:
Action?
Innervation?
Compartment?
- action: flexion of the MTP, PIP, and DIP joints of toes 2-5; inversion of the foot; plantarflexion of the ankle
- innervation: tibial nerve
- compartment: deep posterior of leg
173
What nerve innervates the anterior compartment of the thigh?
the femoral nerve
174
What does the obturator nerve innervate?
- adductor longus
- adductor brevis
- half of the adductor magnus
- gracilis
- obturator externus
175
What nerve innervates the anterior compartment of the leg?
the deep fibular nerve
176
What nerve innervates the lateral compartment of the leg?
the superficial fibular nerve
177
What nerve innervates the posterior compartment of the leg?
the tibial nerve
178
What action is common to both tibialis anterior and tibialis posterior?
inversion of the foot
179
Where does most of the total body calcium reside?
in the calcium salts that make up bone
180
How much of the total body calcium is easily measurable?
| Where is it located?
- about 0.1%
| - in the ECF
181
What symptoms are associated with hypocalcemia?
seizures, muscle spasms, excitability, generalized muscle weakness
182
What symptoms are associate with hypercalcemia?
depression, lethargy, coma, constipation, muscle weakness, kidney stones, increased urine output (bones, stones, moans, groans, and psychiatric overtones)
183
In what forms and percentages is Ca located in the ECF?
| Which is the one that is regulated?
- 40% protein bound (mostly to albumin)
- 50% ionized/free (regulated)
- 10% complexed
184
When you say hypocalcemia, what are you specifically looking at?
low free/ionized Ca in the blood
185
Under what conditions would it be helpful to be in a positive Ca balance?
- children
- pregnant women
- people with broken bones
186
What is the form of vitamin D that you can personally generate?
D3, cholecalciferol
187
Explain the process of vitamin D activation.
the kidney converts 25-D3 to 1,25-D3 using 1a-hydroxylase in a highly regulated process
188
What are the effects of calcitriol in regards to Ca?
| Which one is the most significant effect?
- increases Ca absorption in the GI tract (most)
- increases Ca reabsorption in the kidney (moderate)
- increases bone mineralization (minor)
189
What activates 1a-hydroxylase?
PTH
190
What is active vitamin D a strong suppressor of?
PTH production
191
How does PTH secretion work?
- if there is high Ca, CaSR senses this and blocks the release of PTH
- if there is low Ca, the stimulus is removed, the suppression is removed, and PTH is released
192
What are the effects of PTH in regards to Ca balance?
| What is the largest effect?
- tells osteoblasts to talk to osteoclasts to start bone resorption (largest)
- increases Ca reabsorption in the kidney
- activates vitamin D by stimulating 1a-hydroxylase
- increases GI absorption of Ca
193
Where in the nephron is the bulk of Ca reabsorbed?
the proximal tubule
194
How can you regulate Ca reabsorption in the TAL?
furosemide blocks Ca reabsorption
195
How can you regulate Ca reabsorption in the distal nephron?
- PTH increases reabsorption of Ca
| - thiazide diuretics increase reabsorption of Ca
196
What things stimulate PTH release?
- low Ca
| - high phosphate
197
What does PTH do in regards to phosphate balance?
| What is the net?
- increases production of activated vitamin D via 1a-hydroxylase. However, increased serum phosphate downregulates 1a-hydroxylase, so this is a wash.
- increases bone resorption
- decreases kidney reabsorption of phosphate (leave more in the urine)
- production of FGF23 from bone is stimulated, which also decreases phosphate reabsorption in the kidney and blocks 1a-hydroxylase
-net is loss of K, because the kidney dumps more than is released from the bone
198
Where is most of the phosphate balance regulated in the nephron?
Why?
- in the proximal tubule
| - there is not significant transport of phosphate in any other part of the neprhon
