Comparative anatomy of the haematopoietic system Flashcards
1
Q
Functions of the Haematopoietic system
A
- Provide cells for the dissemination of oxygen and removal of carbon
- Provide the cells that mediate against infection
- Provide the cells that repair injuries & maintains tissues and organs
2
Q
Dissemination of oxygen / removal of carbon dioxide
A
- Production of erythrocytes (erythropoiesis)
- Erythrocytes consist mainly of haemoglobin, haem groups which iron atoms temporarily bind to oxygen in lungs and gills to release through body.
- carries some waste product back from tissues
3
Q
Erythrocytes
A
- restricted to blood vessels
- half life ~50 days
- non-nucleated in mammals, nucleated in other vertebrates
- 96% haemoglobin (metalloprotein)
- can contribute to the immune response
4
Q
Cells that contribute to repair and injury
A
- production of platelets that mediate blood coagulation following damage to a blood vessel
- results in haemostasis
- recruits leukocytes to remove bacteria and debris from a wound via phagocytosis
5
Q
Phagocytic Leukocytes
A
- removes bacteria and debris from wound sites
- has a role in wider homeostatic functions such as tissue remodelling and the removal of dead cells.
6
Q
Stages of developing platelet
A
- Stem cell
- Megakaryocyte Progenitors
- Immature megakaryocyte
- Mature megakaryocyte
- Platelets
7
Q
Platelets
A
- Anucleate cells found only in mammals
- Circulate in blood for ~ 7-10 days
- Responsible for primary haemostasis
- Storage granules
- Birds have nucleated thrombocytes; unable to block damaged arteries
8
Q
Myeloid cells
A
- Derived from myeloid progenitor cells
- Gives rise to granulocytes, monocytes and erythrocytes
- Granulocytes; neutrophils, eosinophils and basophils
- Monocytes become macrophages
9
Q
Neutrophils
A
- large cells, lifespan of 2-3 days
- multilobed nuclei
- phagocytic; kills pathogens via microbicidal mechanisms
10
Q
Macrophages
A
- Large differentiated monocyte
- Perform phagocytosis
- Stimulate immune response
- Tissue repair
- Iron haemostasis
11
Q
Eosinophils
A
- Important in immunity to helminth infections
- Contribute to allergic reactions
12
Q
Basophils
A
- Large cytoplasmic granules
- Participate in inflammatory responses
- Release of histamine, leukotrienes and prostoglandins
13
Q
Monocytes
A
- mononuclear phagocytes
- Kidney-shaped nucleus
- respond to inflammatory stimuli and migrate to infected tissue
14
Q
Dendritic cells
A
- cells related to macrophages and monocytes
- continually sample the environment for antigen
- irregular shape, long cytoplasmic dendrites
15
Q
Mast cells
A
- pass through blood as immature cells & migrate into tissues where they mature as mast cells
- found in connective and mucosal tissues
- important in response to a range of pathogens & allergens
- Release activating factors eg. histamine
