Busy. Please wait.

show password
Forgot Password?

Don't have an account?  Sign up 

Username is available taken
show password


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
We do not share your email address with others. It is only used to allow you to reset your password. For details read our Privacy Policy and Terms of Service.

Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
Didn't know it?
click below
Knew it?
click below
Don't know
Remaining cards (0)
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

Phys Exam 3: Ch 3


What 3 mechanisms prevent blood loss when a blood vessel is cut? 1) Vascular spasm (neural pain reflex, myogenic contraction); 2) Platelet plug; 3) Fibrin clot
Where are platelets formed? About how many are there per mL of blood? In BM from megakaryocytes; 150K-300K
What is a platelet? Fragment of cell w/o nucleus; cytoplasm has actin, myosin, mitochondria, and ATP
What do platelets produce? Prostaglandins & fibrin-stabilizing factor
What do platelets store? Ca & serotonin
What is the half-life of a platelet 8-12 days
What specific surface glycoprotein do platelets have Collagen
How are dead platelets removed? Recycled by macrophages, mostly in the spleen
What happens when platelets contact exposed collage (in the presence of vWF) Begin to form the platelet plug: (1) Swell & extend pseudopods; (2) Become adhesive - esp to collagen; (3) Secrete ADP, serotonin, and thromboxane A2
How are adjacent platelts activated? By the secreted ADP, serotinin, and thromboxane A2
Are serotonin & thromboxane A2 vasodilators or vasoconstrictors? Potent vasoconstrictors
How quickly is blood clot formation initiated? W/in seconds after injury
What substances does formation of a blood clot require? platelets, plasma proteins,and the vessel wall
Discuss fibrin clot contraction Contracts w/in a few minutes. Contraction is due to (1) actin & myosin in platelets bound in the clot, (2) Ca from the platelets, (3) covalent cross-links from fibrin-stabilizing factor
Created by: hclark86



Use these flashcards to help memorize information. Look at the large card and try to recall what is on the other side. Then click the card to flip it. If you knew the answer, click the green Know box. Otherwise, click the red Don't know box.

When you've placed seven or more cards in the Don't know box, click "retry" to try those cards again.

If you've accidentally put the card in the wrong box, just click on the card to take it out of the box.

You can also use your keyboard to move the cards as follows:

If you are logged in to your account, this website will remember which cards you know and don't know so that they are in the same box the next time you log in.

When you need a break, try one of the other activities listed below the flashcards like Matching, Snowman, or Hungry Bug. Although it may feel like you're playing a game, your brain is still making more connections with the information to help you out.

To see how well you know the information, try the Quiz or Test activity.

Pass complete!

"Know" box contains:
Time elapsed:
restart all cards