3RD HEMA - Part 5

Question 1

Anchors the plasma membrane.

Answer 1

Actins

Question 2

Formed by: Actins

Answer 2

MICROFILAMENTS

Question 3

○ Also present throughout the
platelet cytoplasm
○ Globular and amorphous (in
resting platelets)

Answer 3

MICROFILAMENTS (Actins)

Question 4

○ As cytoplasmic calcium concentration increases → actin becomes filamentous and contractile

Answer 4

MICROFILAMENTS (Actins)

Question 4

What protein makes the microtubules?

Answer 4

Tubulin

Question 5

Location of the Microfilaments

Answer 5

Between the microtubules and the membrane

Question 6

Cytoplasm: Also contains intermediate filaments

Answer 6

(Desmin and Vimentin)

Question 7

Which connects with the actin and the tubules → maintaining the platelet shape.

Answer 7

Desmin and Vimentin

Question 8

Flow through the SCCS

Answer 8

ALPHA GRANULES & LYSOSOMES

Question 9

Travel to the plasma membrane

Answer 9

DENSE GRANULES

Question 10

50-80 granules per platelet
○ Most abundant of the 3 different kinds

Answer 10

ALPHA GRANULES

Question 11

● Most of the a-granule contents are proteins that participate in
secondary hemostasis (coagulation)

Answer 11

ALPHA GRANULES

Question 12

As the platelets becomes
activated

Answer 12

Alpha granule membrane fuse
with SCCS
○ Surface connected canalicular system (SCCS)

Question 13

● Stain medium-gray (Osmium dye transmission electron microscopy preparations)

Answer 13

ALPHA GRANULES

Question 14

In the nearby environment, the contents of the a-granule:

Answer 14

● Participate in platelet adhesion
● Participate in platelet aggregation
● Support plasma coagulation

Question 15

Alpha Granules

Contain coagulation factors

Answer 15

● Fibrinogen
● vWF
● HMWK

Question 15

α-granules (but not in the
cytoplasm)

Answer 15

● HMWK
● PAI-1 (plasminogen activator
inhibitor-1)
● Plasminogen
● Protein C inhibitor

Question 16

α-granules (but not in the
cytoplasm)

Inhibits heparin:

Answer 16

● β-thromboglobulin
● PF-4 (platelet factor-4)

Question 16

α-granules (but not in the cytoplasm)

Supports mitosis of vascular fibroblast and smooth muscle cells

Answer 16

● EGF (endothelial growth factor)
● PDGF (platelet-derived growth
factor)
● TGF-β (transforming growth
factor-β)

Question 17

α-granules and platelet
cytoplasm

Answer 17

● Fibrinogen
● Fibronectin
● Albumin
● Immunoglobulins
● VWF
● Thrombospondin
● Factor V (F5)

Question 18

α-granule membrane

Answer 18

● P-selectin

Question 19

α-granule membrane and
plasma membrane

Answer 19

● GP IIb/IIIa (2b/3a)
● GP IV (4)
● GP Ib/IX/V (1b/9/5)

Question 20

Which of the following platelet granules contain coagulation factors?

A. Alpha granules
B. Dense granules
C. Lysosomes
D. None of the Above

Answer 20

A. Alpha granules

Question 21

● They migrate to the plasma membrane and release their contents directly into the plasma
upon platelet activation

Answer 21

DENSE GRANULES/ DELTA GRANULES

Question 21

A.k.a DELTA GRANULES

Answer 21

DENSE GRANULES/ DELTA GRANULES

Question 22

● 2-7 dense granules per platelet ● Stain black (opaque) when treated with osmium in transmission electron microscopy

Answer 22

DENSE GRANULES/ DELTA GRANULES

Question 23

● Vasoconstrictors ● Platelet agonists that intensify primary hemostasis

Answer 23

DENSE GRANULES/ DELTA GRANULES

Question 24

A substance that initiates a response when combined with a receptor

Answer 24

AGONIST

Question 25

“MP-CHASE” mnemonics

Answer 25

● Magnesium ● Phosphate ● Calcium ● Histamine ● Adenosine diphosphate (ADP) and Adenosine triphosphate (ATP) ● Serotonin/ 5-hydroxytryptamine (5-HT) ● Epinephrine/ Adrenaline

Question 26

All of the following are found in the dense granules EXCEPT: a. Epinephrine b. Fibrinogen c. Serotonin d. Magnesium

Answer 26

b. Fibrinogen Fibrinogen is found in the alpha granules NOT dense granules. Dense granules contain the MP-CHASE.

Question 27

All of the following are found in the alpha granules EXCEPT: a. Platelet Factor 4 b. PDGF c. Fibrinogen d. Adrenaline/ Epinephrine

Answer 27

d. Adrenaline/ Epinephrine

Question 28

Supports neighboring platelet aggregation by binding to P2Y1 and P2Y12.

Answer 28

ADP

Question 28

Function is unknown, but ATP release is detectable upon platelet activation.

Answer 28

ATP

Question 29

Action: Alpha Granules or Dense/Delta Granules ● The alpha-granule membrane fuses with the SCCS. ● Participate in platelet adhesion and aggregation and support plasma coagulation.

Answer 29

Alpha Granules

Question 29

Vasoconstrictors that bind/ endothelial cells and platelet membranes

Answer 29

Serotonin (5-Hydroxytryptamine)

Question 29

Divalent cations support platelet activation and coagulation.

Answer 29

Calcium and Magnesium (Ca2+ and Mg2+)

Question 30

Granules: Alpha Granules or Dense/Delta Granules ● 50–80 granules in each platelet

Answer 30

Alpha Granules

Question 31

Granules: Alpha Granules or Dense/Delta Granules ● 2–7 dense granules per platelet

Answer 31

Dense/Delta Granules

Question 32

Stain: Alpha Granules or Dense/Delta Granules Black (opaque) when treated with osmium in transmission electron microscopy

Answer 32

Dense/Delta Granules

Question 32

Stain: Alpha Granules or Dense/Delta Granules Medium-gray (Osmium-dye transmission electron microscopy preparations)

Answer 32

Alpha Granules

Question 33

Proteins and components present: Alpha Granules or Dense/Delta Granules ● β-thromboglobulin ● PF-4 (platelet factor-4) ● HMWK ● PAI-1 (plasminogen activator inhibitor-1). ● Plasminogen ● Protein C inhibitor ● EGF (endothelial growth factor) ● PDGF (platelet-derived growth factor) ● TGF-β (transforming growth factor-β) ● Fibrinogen ● Fibronectin ● Albumin ● Immunoglobulins ● VWF ● Thrombospondin ● Factor V (F5) ● P-selectin ● GP IIb/IIIa (2b/3a) ● GP IV (4) ● GP Ib/IX/V (1b/9/5)

Answer 33

Alpha Granules

Question 34

Hemostasis: Alpha Granules or Dense/Delta Granules Secondary hemostasis

Answer 34

Alpha Granules

Question 34

Action: Alpha Granules or Dense/Delta Granules Migrate to the plasma membrane and release their contents directly into the plasma upon platelet activation.

Answer 34

Dense/Delta Granules

Question 35

Hemostasis: Alpha Granules or Dense/Delta Granules Primary hemostasis

Answer 35

Dense/Delta Granules

Question 36

● Few in number ● Stain positive for arylsulfatase, B-glucuronidase, acid phosphatase, and catalase

Answer 36

LYSOSOMES

Question 37

Proteins and components present: Alpha Granules or Dense/Delta Granules 2–7 dense granules per platelet

Answer 37

Dense/Delta Granules

Question 38

● ____________’ contents flow through the SCCS. ● __________ probably digest vessel wall matrix components during in vivo aggregation and may also digest autophagic debris

Answer 38

LYSOSOMES

Question 38

● Glycocalyx is less developed in the _____ and lacks some of the glycoprotein receptors present on the platelet surface

Answer 38

SURFACE-CONNECTED CANALICULAR SYSTEM (SCCS)

Question 39

● The plasma membrane invades the platelet interior, producing _____.

Answer 39

SURFACE-CONNECTED CANALICULAR SYSTEM (SCCS)

Question 40

SCCS is the route for:

Answer 40

- Endocytosis - Secretion of a-granule contents - Secretion of lysosome contents

Question 41

● These enzymes include: - Support the eicosanoid synthesis pathway that produces thromboxane A2 (3)

Answer 41

■ Phospholipase A2 ■ Cyclooxygenase ■ Thromboxane synthetase

Question 41

“Control center” for platelet activation

Answer 41

DENSE TUBULAR SYSTEM (DTS)

Question 42

● Parallel and closely aligned to the SCCS ● A condensed remnant of the rough endoplasmic reticulum

Answer 42

DENSE TUBULAR SYSTEM (DTS)

Question 43

● Sequesters calcium and bears a series of enzymes that support platelet activation.

Answer 43

DENSE TUBULAR SYSTEM (DTS)

Question 44

- Supports the production of inositol triphosphate (IP3) and diacylglycerol (DAG) (1)

Answer 44

■ Phospholipase C

Question 45

Brand name from Bayer Company

Answer 45

ASPIRIN

Question 46

Also known as: acetylsalicylic acid

Answer 46

ASPIRIN

Question 47

● Most frequently used antiplatelet therapy or drug ● Cyclooxygenase inhibitor

Answer 47

ASPIRIN

Question 48

Parts of platelets that can be found using the light microscope:

Answer 48

● Chromomere and Hyalomere ● For smaller structures, use an electron microscope. ● To see the ultrastructure of the platelet ○ Molecular sequencing ○ Flow cytometry

Question 50

For smaller structures,

Answer 50

use an electron microscope.