Model 12 blood

what is the composition a bone? for example the femur?

• bone & cartilage tissue

• Red marrow & blood (connective tissues)

• Blood vessels (endothelial tissue)

• Yellow marros (adipose tissue, a type of connective tissue)

Hydroxyapatite (HAp)

a naturally occurring mineral that forms the main component of bones and teeth, particularly in the enamel, the hardest tissue in the body

Yes, bones are primarily made of hydroxyapatite. This calcium phosphate compound forms the main inorganic component of bone, accounting for about 65-70% of its mass. It's a key ingredient in bone's strength and hardness, along with collagen, which provides flexibility

Trabeculae

are lattice-shaped ribbons of bone

are arranged to accommodate the external stress acting on the bone. The trabeculae undergo adaptive change if new stresses are placed on the bone

what is compact bone

compact bone is dense and forms the hard extenrior of bones. compact bone accounts for 80% of the total bone mass of an adult human skeleton

Compact bone provides support for the body and provides protection for organs, among other fuctions

Can trabeculae undergo adaptive changes? why?

yes, is new stresses are placed on the bone, trabeculae undergo adaptive changes

How we new that a bone is a living tissue give example?

femur broken before the death of the person. the fractured bone was not ptoperly aligned. new bone grwoth re-fused the fracture ends

femur broken after the death of the person. note that the fracture did not heal

Chondrocytes

cartilage cells that secrete extracellular matrix(rigid bc of hydroxypatites) (collagen) scaffold for bone to grow on (he extracellular matrix (ECM) is a network of proteins (like collagen) and other molecules that provide structural support outside the cells. A scaffold in this context refers to a framework that gives shape and support for cells and tissues to form and grow on.)

• Secrete extracellular matrix

• collagen

• proteoglycans

• Cartilage

Osteoblast

cells that take calcium form plasma and use it to build bone

secrete calcium and phosphate which crystalize in the ECM as hydroxyapatite

• secretes Ca2+ and PO43-, collagen and proteoglycans and cytokines

• PTH and vitamin D3 control osteoblast function

• PHT (parathyroid hormone) and vitamin D3 make osteoblast to release cytokines that will make macrophage to diffuse to osteoclast which will absorb Ca2+

Osteoclasts

cells that resorb bone; these cells remove calcium form bone and deposit it in plasma

• acid secretion dissolves bone matrix

• bone resorption

• secrete acid and enzymes that dissolve calcium phosphate in bone

osteocytes

mature, inactive osteoblast forund in bones that have stopped lengthening

what is cartilage?

• connective tissue composed of chondrocytes that secrete large amount of collagen (extracellular matric protein)

• Chondrocytes also secrete proteoglycans (glycosylated protein)

• together collagen and proteoglycans make up the bulk of the extracellular matrix and impart the semi-rigid structural properties characteristic of cartilgae

epiphyseal plate

by the time the fetal skeleton is fully formed, cartilage only remains at the joint surfaces (articular cartilage) and the epiphyseal plates (site of longitudinal bone growth)

what is the difference between Gigantism and Acromegaly?

gigatism person developed a pitutary tumor during childhood

acromegaly person develop a pituitary tumore during adulthood.

in both cases growth hormone was overproduced by the tumor cells

what does platelets have?

• fragments of megakaryocytes (large cells)

• No nucleus

• have mitochondria, smooth endoplasmic reticulum and vesicles (granules) filled with cytokines and other signaling molecules

• smooth surface when inactive plateles are small disk-like cell fragments

• actived platelets (shown enlarged) develop a spiky outer surface and adhere to each other

• collagen is a ligand for plateles to become aggregation

what is the most common protein in blood?

albumins: major contributors to plasma colloid osmotic pressure

Where does hematopoiesis occurs?

• red marrow: blood cell production

• yellow marrow: large number of adipocytes (fat cells) impart yellow color. in chronic hypoxia, yellow marrow can be converted to red marrow to increase blood cells

what is differentiation?

the process of activating a select set of genes to produce gene products found in only a specific mature cell type

pluripotent what can develop?

a stem cell that can develop into many but not all cell types

• Lymphocyte

• Monocyte, neutrophil, platelets and erythrocyte

what does red bone marrow has? and where is form?

has pluripotent stem cells and if formed in the spaces between the mineralized bone

hematopoiesis- blood cells develop in red bone marrow in a process

is supporting tissue is called stroma

venous sinuses, highly vascular

example of white blood cells

• function: immune defense

• Lymphocytes: involved in specific immune response

  • T cells

  • B cells

  • Natural killer cells

• monocytes: large phagocytic cells

  • can differentiate into macrophages (phagocytic) and dendritic cells (phagocytic)

• neutrophils: neutral dye, granules, phagocytic

what is tissue factor (TF)

is a transmembrane protein present on smooth muscle cells (and fibroblasts) in the subendothelial space. tissue factor is exposed when the vessel wall is damaged

tissue factor is the initiator the extrinsic clotting cascade, which is the predominant coagulation pathway in vivo

What is coagulation, clot and fibrinolysis? steps

coagulation: thrombin makes fibrinogen to fibrin polymer

clot: fibrin polymer

fibrinolysis: fibrin polymer— plasmin— fibrin fragments

tissue plasminogen activator activates plasmin