Quiz 7 Flashcards
What things make fatty acids good for energy substrates and storage?
They are highly reduced, inert, they pack tightly together, hydrophobic (so they do not affect they osmolarity of the cell)
Do chylomicrons transport triglycerides or free fatty acids? What about albumin?
Chylomicrons transport triglycerides.
Albumin transports free fatty acids.
What occurs when a chylomicrons reaches its target location? What enzyme is involved?
ApoC-II (on the chylomicron) activates lipoprotein lipase. Lipoprotein lipase breaks down the chylomicrons and converts the triacylglycerols to FA and glycerol which can then be taken up by the tissue
Where are chylomicrons synthesized?
In the ER of Enterocytes (absorptive small intestine cells)
What are apolipoproteins?
They are proteins that bind to lipids to form lipoproteins. They serve diverse functions such as activating enzymes and receptors.
Is a chylomicron a lipoprotein or an apolipoprotein?
Lipoprotein. Apolipoproteins are just associated with lipoproteins
What are the four classes of lipoproteins? What are their relative sizes?
Chylomicrons (extra large)
VLDLs (large)
LDL (Medium)
HDL (small)
Which lipoproteins contain the most protein? (In descending order)
1) HDL
2) LDL
3) VLDL
4) Chylomicron
Which lipoproteins contain the most triglycerides in descending order?
1) chylomicron
2) VLDL
3) LDL
4) HDL
Are lipoproteins composed of a mono layer or a bilayer?
Monolayer of phospholipids
Which lipoprotein contains the most cholesterol (in descending order)?
1) LDL
2) HDL
3) VLDL
4) Chylomicron
What happens to the chylomicron after it has dumped off its lipids in the target tissue?
The chylomicron remnants go back to the liver. This is where the endogenous pathway begins
The liver produces what lipoprotein to deliver fatty acids to the tissues? What happens after? (Two things)
VLDL.
After VLDL dumps off its fatty acids to the tissue, it becomes LDL. The LDL can either go back to the liver to recycle back to VLDL orrrr it can dump off their excess cholesterol to macrophages in the vasculature.
What does HDL do?
HDL takes up the cholesterol obtained in the macrophages (foam cells) and delivers the cholesterol back to the liver.
Explain how lipoproteins are internalized by target tissue cells. (5 steps)
1) LDL receptor binds to apoB-100 on lipoprotein
2) LDL is internalized in endosome
3) LDL receptors segregate from vehicle and recycled to surface
4) endosome fuses with lysosome
5) enzymes in lysosome break down LDL into aa, FA, and cholesterol
Where is perilipin located? What is its function?
It is located on the surface of lipid droplets in adipose cells. Perilipin functions to stabilize the lipid droplet.
What does perilipin do once it is phosphorylated by PKA?
It will activate CGI (compatible gene indicator)
What does CGI do once it is activated?
Comparative gene indicator will go on to phosphorylate ATGL (adipose triglyceride lipase)
What does ATGL do once activated?
It will break up triacylglycerols into diacylglycerides and monoacylglycerides.
What two things does PKA do in an adipose cell?
Phosphorylates perilipin
Phosphorylates hormone sensitive lipase (HSL)
What does HSL (hormone sensitive lipase) do once phosphorylated?
HSL will break diacylglycerides down to monoacylglycerides
What is the role of MGL (monoglyceride lipase)?
MGL removes glycerol from monoacylglycerides to form free fatty acids. The free fatty acids can then be taken up in the blood.
Once fatty acids are released into the blood, they are transported by ___ and taken up into cells via ____
1) serum albumin
2) fatty acid transporters
How is glycerol catabolized? What is it turned into? What is produced in the process?
It will be converted into Glyceraldehyde-3- phosphate to enter glycolysis. In this process, you use 1 ATP and create one NADH
What will the fatty acids form?
Fatty acyl coAs
Where is carnitine acyltransferase I and II located?
I is located in the outer mitochondrial membrane
II is located in the inner mitochondrial membrane
How is a fatty acyl coA molecule transported into the matrix of a mitochondria?
The fatty acyl coA is attached to a carnitine molecule via carnitine acyltransferase I. The carnitine+fatty acid is transported into the intermembrane space. Then it goes through a carnitine transporter where carnitine goes into the intermembrane space while carnitine+fatty acid goes into the matrix. The carnitine is removed from the complex via carnitine acyltransferase II
In fatty acid oxidation… Which carbon gets oxidized?
The beta carbon
What are the products per oxidation step?
1 acetyl coA
1 NADH
1 FADH2
What is special about the first step of B oxidation?
The enzyme is acyl-coA dehydrogenase which feeds directly into the electron transport chain
What enzymes of B oxidation are directly correlated with the electron transport chain?
Acyl-coA dehydrogenase
B hydroxylacyl-coA dehydrogenase
Since B oxidation involves breaking the carbon chain into two carbon segments, what happens to odd numbered carbon fatty acids?
Odd carbon and unsaturated fatty acids must undergo extra steps
How can fatty acids be converted to glucose?
Broken down into acetyl coA, enter citric acid cycle, oxaloacetate can be converted to glucose via Gluconeogenesis
What can happen to acetyl coA if Gluconeogenesis is saturated?
It can form ketone bodies
What are the three ketone bodies?
Acetoacetate
B-hydroxybuterate
Acetone
What are some things that ketone bodies can do?
Release enzyme coA
Can be ulitilezed as a fuel source
What are some things that can cause an excess of acetyl coA
Excess dietary carbohydrates and proteins
What is insulin’s role in the formation of fatty acids?
It promotes the formation of acetyl-coA from carbohydrates and proteins
It promotes the formation of fatty acids from acetyl coA
What are the five stages of fatty acid synthesis?
1) transport acetyl coA to cytoplasm
2) carboxylate on of acetyl coA into malonyl coA
3) fatty acid synthase combines acetyl coA and malonyl coA to start a chain
4) fatty acid synthase adds malonyl coA carbons to create palmitate
5) fatty acids modified in ER
where are the three locations in which fatty acid synthesis takes place?
Cytoplasm
Mitochondria
ER
Acetyl coA is produced in the ____ but lipid synthesis occurs in the ____
1) matrix
2) cytoplasm
How is acetyl coA transported into the cytoplasm from the matrix?
Acetyl coA is attached to citrate and goes through the citrate transporter
Once citrate + acetyl coA is in. The cytosol, how is it converted back. To. Acetyl coA?
Citrate lyase
How is oxaloacetate replenished. In the. Matrix???
The citrate shuttle. The malate a-ketogluterate transporter brings malate in orrrr the pyruvate transporter brings pyruvate in.
What is the role of acetyl-coA carboxylate?
It carboxylates acetyl-coA to form malonyl-coA (which is necessary for acyl chain initiation and synthesis
There are two types of fatty acid synthase. Which type do vertebrates and fungi have? What about bacteria and plants?
Vertebrates and fungi = FAS I
Bacteria and plants = FAS II
What type of fatty acids are produced by fatty acid synthase I?
Only saturated 16 carbon FA. PALMITATE
What is the rate determining step in lipid synthesis?
Conversation of acetyl coA to form malonyl coA by ACC
What is the role of acyl carrier protein in lipid synthesis? What is a critical component of this protein?
It is a FAS prosthetic group. It shuttles malonyl-coA to Fatty acid synthase to help build the FA chains
Needs pantothenic acid (vitamin B5)
Explain the steps of fatty acid synthasis
1) acetyl-coA is carboxylated by ACC to form malonyl coA
2) Malonyl coA + acetyl coA +FAS = condensation reaction and CO2 is released
3) With the use of NADPH the B carbon is reduced (the carbon from acetyl coA)
4) B carbon is dehydrated
5) B carbon is reduced (with NADPH)
Every new two carbons that are added to the FA chain are from malonyl coA or acetyl coA?
Malonyl coA
The omega carbon comes from acetyl coA or malonyl coA?
Acetyl coA
What are the two sources of NADPH that are required for FA synthesis?
Pentose phosphate pathway and the malic enzyme (converts malate to pyruvate)
What are two essential fatty acids that are produced from plants?
A linoleic acid and linoleic acid
Is acetyl coA Carboxylase active in its phosphorylated or dephosphorylated form? What is insulin’s effect on ACC?
ACC is active in its dephosphorylated form
Insulin dephosphorylates ACC to activate it
What is glucagon’ effect on fatty acid synthesis?
It inhibits it by deactivating ACC (phosphorylating Acetyl coA Carboxylase)
the presence of Malonyl coA has what affect one Fatty acid B oxidation? How does this work?
It will inhibit fatty acid B oxidation
It does this by inhibiting the action of carnitine acyl-transferase. This prevents fatty acids from entering the mitochondria for B oxidation
How is it that ACC regulates both fatty acid synthesis and fatty acid oxidation?
When ACC is active, it converts acetyl-coA to Malonyl-coA. the presence of malonyl coA isn’t just necessary for fatty acid synthesis, it inhibits fatty acid B oxidation by Inhibiton of carnitine acyl-transferase
What is necessary to form phosphatidic acid?
Glucose and glycerol
What is phosphatidic acid and what is it used for?
Phosphatidic acid is like a triglyceride except one of the 3 backbone carbons has a phosphate group instead.
Phosphatidic acid is thus a precursor to “a whole slew” of molecules such as triacylglycerols, phospholipids, and diacylglycerides
Where do changes to phosphatidic acid take place?
In the ER
What is the precursor for cholesterol?
Acetyl coA. (Acetate?)
What are some things that progesterone can be converted to?
What is the precursor to progesterone?
What is the precursor to that?
Cortisol
Corticosterone
Testosterone
the precursor to progesterone is pregnenalone
The precursor to pregnenalone is cholesterol.
Explain how/why foam cells form in blood vessels?
Oxidized lipoproteins stick to ECM in blood vessels
Monocytes are attracted to areas of oxidized lipoproteins.
Monocytes differentiate into foam cells to ingest the lipoproteins
How does plaque form in the vessels?
Not enough HDLs to take away the cholesterol from the foam cells. The foam cells die and stack on top of each other.
Where does most fatty acid synthesis take place/
The liver
Where do most muscles attach on the hyoid bone?
To the body
What are the functions of the anterior strap muscles?
Depress mandible, elevate ribs, elevate/depress larynx
What is the primary tissue type in the superficial cervical fascia? What is the only muscle located within this layer?
Superficial cervical fascia is like hypodermis (mostly fat)
The only muscle in the superficial cervical fascia is the platysma muscle
Why is the platysma difficult to identify?
It’s very thin (about one or two fibers thick)
What is the most superficial layer of the deep fascia?
Investing fascia
What muscles are in the investing fascia?
Sternocleidomastoid and trapezius. (Both innervated by the accessory nerve)
What are the different layers of the pre tracheal fascia?
Muscular fascia
Visceral fascia
Buccopharyngeal fascia
What muscle is within the muscular fascia layer of the pre tracheal fascia?
Infra hyoid muscles.
What structure is invested by the visceral layer of the pre tracheal fascia?
Thyroid gland
Explain the buccopharyngeal fascia. What two structures are within it?
The buccopharyngeal fascia stretches across either side of the thymus. In between the visceral layer and buccopharyngeal fascia is the trachea and esophagus
What muscles are invested by the prevertebral fascia?
Deep cervical muscles
Levator scapulae muscle
Scalene muscles
Longus Coli muscle
What layer of the deep fascia is the alar fascia part of? What is it?
Prevertebral fascia
The alar fascia is the point where the prevertebral fascia splits over the sympathetic trunk
Where is the retro pharyngeal space located?
In between the buccopharyngeal fascia and the alar fascia
Where is the alar space located?
In between the alar fascia and the prevertebral fascia
if an infection breaks into the alar space or retro pharyngeal space, where can the infection spread?
To the mediastinum
What structures are invested in the carotid sheath?
IJV
Carotid artery
Vagus nerve
The nerves branching off of the ansa are mostly what type of nerves?
They are motor nerves for neck muscles
How can you tell the internal carotid artery apart from the external carotid artery?
The internal carotid has no branches.
Has a carotid sinus and carotid body
What will you find in the carotid sinus? What about the carotid body?
Barroreceptors in the carotid sinus
Chemoreceptors in the carotid body
Which is bigger the carotid sinus or the carotid body?
The carotid sinus is much bigger
Starting from inferior to superior, what is the order of branching off of the external carotid artery?
Superior thyroid Ascending pharyngeal Lingual Fascial Occipital Posterior auricular Maxillary Superficial temporal (note that the superficial temporal and maxillary artery bifurcate the external carotid so the external carotid is no more
All of the fascial veins drain into the ___
Internal and external jugular veins
What vein drains the brain?
Internal jugular. Note that the external jugular only drains the face
What vein allows for anastomoses between the internal and external jugular veins?
The retro mandibular vein
The pterygoid plexus allows blood to drain into the ____
Cavernous sinus
What is the main action of the supra hyoid muscles?
Elevate the hyoid bone and larynx
What nerve innervates the anterior belly of the digastric muscle?
CN V3
What nerve innervates the stylohyoid muscle?
The fascial nerve
What is the function of the infra hyoid muscles?
They depress the hyoid bone and larynx
If the supra hyoid and infra hyoid muscles work together, what is their action?
Depression of the mandible
What are the borders for the posterior triangle?
SCM, Trapezius, clavicle
What two structures arise out of the posterior triangle superficially?
External jugular vein and cervical plexus
What fascial layer is the roof of the posterior triangle? What fascial layer makes up the floor of the posterior triangle?
Investing fascia = roof
Preverterbral fascia = floor
If you expose the floor of the posterior triangle, what muscles will you find?
The inter scalene triangle which includes the anterior scalene, brachial plexus, and middle scalene
What muscles will you find in the floor of the posterior triangle excluding the inter scalene triangle?
Posterior scalene muscle
Splenius capitis
Levetor scapula
What arteries will you find in the floor of the posterior triangle?
Transverse cervical artery (comes off of the subclavian) and supra scapular artery
What are the borders of the muscular triangle of the anterior triangle?
Superior belly of omohyoid
Midline
SCM
What are the borders of the sub mental triangle of the anterior triangle?
Anterior digastric
Anterior digastric
Hyoid bone
What are the borders of the submandibular triangle of the anterior triangle?
Anterior digastric
Posterior digastric
Mandible
What structures are found in the submandibular triangle?
Submandibular gland
Submandibular lymph nodes
Lingual and facial arteries
Hypoglossal nerve
What are the borders of the carotid triangle of the anterior triangle?
Superior omohyoid
Posterior digastric
SCM
What structures are found in the carotid triangle?
The carotid arteries (common, external, internal)
Internal jugular vein
CN X XI and XII
Some of the cervical plexus
What nerves innervate (visceral sensory) the carotid body and sinus?
Glossopharyngeal and vagus nerve
What nerve has sensory and motor functions of the Superior portions of the larynx? What about inferior portion?
Laryngeal nerve.
The inferior portion is innervated by the recurrent laryngeal nerve (branches off of the vagus)
What 3 components make up the visceral triangle?
Thyroid/parathyroid
Trachea
Esophagus
What is the isthmus of the thyroid?
The center narrow portion of they thyroid that connects the left and right lobes
What are the arteries and veins that feed/drain the thyroid?
Superior and inferior thyroid arteries and superior laryngeal artery
Superior, middle, and inferior thyroid veins
The thyroid cartilage is located in between what two structures?
Hyoid bone and thyroid
Which branches off of the subclavian artery first, the vertebral artery or the thyrocervical trunk?
Vertebral artery
The vertebral artery runs between what two muscles?
Anterior scalene and longus Coli
How does the vertebral artery enter the skull?
Foramen magnum
The inferior thyroid artery branches off from what artery?
Thyrocervical trunk
What artery branches off of the inferior thyroid artery?
Ascending cervical artery
What three arteries branch off of the thyrocervical trunk?
Inferior thyroid
Transverse cervical
Supra scapular
Where does the thoracic duct drain?
Into the subclavian vein just lateral to the IJV
All exocrine gland cells are what type of cells?
Epithelial cells
True or false, endocrine glands have ducts.
False, only exocrine glands have ducts
How do endocrine cells release their contents?
Exocytosis
True or false, endocrine glands may be made up of epithelial or non epithelial cells
True
What are the three types of exocrine glands and how do they release their contents?
Merocrine- exocytosis
Holocrine - cell disintegration
Apocrine - budding
What type of glands are the exocrine glands of the pancreas?
Merocrine
Explain the activation of the protease zymogens
Trypsinogen is activated by enterokinase to become trypsin
Trypsin activates chymotrypsinogen to become chymotrypsin
Elastase is also activated by trypsin
What cells of the exocrine glands secrete the zymogens? What cells secrete the alkaline fluid to flush out the zymogens?
Acinar cells secrete the zymogens
Controacinar cells secrete the alkaline fluid
What two hormones induce the controacinar cells to produces the alkaline solution? Where do these hormones come from?
Cholecystokinin - I cells
Secretin - S cells
What are the four cells of the islets of langerhans? What do they secrete?
A cells - glucagon
B cells - insulin
D cells - somatostatin (inhibits GI and pancreatic endocrine and exocrine function)
PP cells - pancreatic polypeptide (inhibits pancreatic exocrine function)
Name 4 functions of the liver
Blood reservoir (30%)
Bile secretion
Detoxification
Metabolic homeostasis
What are the three major cell types of the liver and what do they do?
Hepatocytes- metabolism, produce bile, detoxifies stuff (polarized epithelial cells)
Kupffer cells - macrophages
Sinusoidal epithelial cells - ?
What are the two sources of blood to the liver? What are their relative proportions?
Hepatic artery - 30%
Portal vein - 70%
Explain the classic hepatic lobule
Hexagonal prism
Blood from hepatic artery and portal vein drains through the central vein
Endocrine focus
Explain the portal lobule
Forms a triangle in between three central veins
Bile drains from hepatocytes to the bile ducts. (Bile duct is in center of the lobule)
Exocrine focus
Explain the hepatic acinus
Gradient of hepatocytes oxygenation
Zone I - peri portal zone high in O2 (Most active in regulating blood sugar) Zone II - intermediate zone Zone III - peripheral zone low in O2 (Highest con. Of detoxification enzymes)
Explain phase I liver detoxification
Occurs in Zone III of the hepatic acinus (oxygen poor)
Utilizes cytochromes to make the drugs polar by a REDOX reaction
This leads to the production of a metabolite to be used in subsequent steps
Explain phase II liver detoxification
Occurs in Zone I of the hepatic acinus (oxygen rich)
The metabolite produced in phase I is conjugated to hydrophilic molecules (glucoronic acid) to make them soluble
This allows the transportation of the metabolites into the bile duct or back into the blood to get filtered by kidneys
What roles do CCK and secretin play in the gall bladder?
CCK stimulates bile release by relaxing the hepatopancreatic sphincter and causing smooth muscle contractions of gall bladder
Secretin stimulates bicarbonate secretion into the bile
How does Malonyl coA inhibit B oxidation?
It inhibits the carnitine acyl-transferase 1 so that fatty acid carnitine cannot be transported into the intermembrane space, and thus the matrix (where B oxidation occurs)
How is phosphatidic acid formed? How much energy is required?
Glucose + glycerol form Glycerol-3-phosphate. This then undergoes two acyl transfers to form phosphatidic acid.
This requires 1 NADH and 3 ATP
What nerve innervates the anterior digastric?
Mandibular branch of V3
True or false, the scalene muscles attach to C1 an c2.
False
What nerve goes to the carotid body and sinus?
Glossopharyngeal (Vagus just goes to the carotid body)
The vertebral artery runs in between what two muscles?
Anterior scalene and longus Coli
How does the vertebral artery enter the skull?
Foramen magnum
how does the internal carotid artery enter the skull?
Carotid canal
True or false…. The external jugular vein branches off of the subclavian vein
True
True or false…. Insulin inhibits the release of glucagon from A cells
True
What is the difference between the effects of D cells and PP cells?
D cells will inhibit the exocrine and endocrine function of the pancreas whereas the the PP cells only inhibit the exocrine function of the pancreas
What is the structure found in the center of a portal lobule?
Bile duct
