Medicine Sem 1 > physiology week 9 > Flashcards

physiology week 9 Flashcards

-RBC,Anemia and polycythemia (104 cards)

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1
Q

What is the primary role of red blood cells

A
  • Transports hemoglobin, which carries oxygen from lungs to tissues
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2
Q

Why must the hemoglobin remain inside the red blood cells

A
  • To avoid loss through the capillary and kidney membranes
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3
Q

What else does red blood cells contain

A
  • Carbonic anhydrase, which is an enzyme that catalyses the conversion of C02 and water into carbonic acid
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4
Q

What are the roles of carbonic anhydrase

A
  • An enzyme that catalyses the conversion of c02 and water into carbonic acid
  • It enables efficent C02 transport as bicarbonate ions
  • Contributes to acid-base buffering in the blood due to hemoglobin properties
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5
Q

What is the shaoe and size of RBC

A
  • Has a biconcave disc
  • Volume of 90-95 cubic meters
  • Has a flexible bony like structure which allows the deformation for passage through capillaries without rupture
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5
Q

What are the sites of red blood cell production in the embroyonic stage:
-Early weeks
-Middle trimester
-Last trimester+ after birth

A
  • Early weeks:
    -Primitive nucleated red blood cells are produced in the yolk sac
    Middle trimester
    -The liver is the primary ogran for RBC and some is also produced in the spleen and lymph
    LAST TRIMESTER & AFTER BIRTH
    -RBC production shifts to the bone marrow
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5
Q

During childhood where are red blood cells produced

A
  • In the marrow of nearly all bones up to 5 years of age
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6
Q

During Adulthood where is red blood cells produced

A
  • In the membranous bones:
    -Vertberae
    -Sternum
    -Ribs
    -ilia
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7
Q

What is the aging effect in relation to bone marrow

A
  • Bone marrow productivity decreases as age increases even in membranous bones
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8
Q

Where do circulating red blood cells orginate from

A
  • Multipotential hematopoietic stem cells (HSCs) in the bone marrow
  • The stem cells self renew to maintain their supply, but their numbers decrease with age
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9
Q

What happens as HSCs( hematopoietic stem cells) reproduce

A

-Most cells differentiate into specific cell types while a small portions remains a HSCs

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10
Q
  • Where do commited cells arise from
A
  • They arise from multipotent stem cells
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11
Q

Whay do commited stem cells produce

A
  • They produce colonies of specific blood cells such as
  • CFU-E , which forms erythrocytes)RBC)
    -CFU-GM, which formes granulocytes and monocytes
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12
Q

What are growth inducers
And how many exist

A
  • They are proteins that control growth and reproduction of stem cells
  • At least 4 major growth inducers exist
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13
Q

Name an example of a growth inducer and its role

A
  • Interleukin -3 and it promotes the growth of nearly all types of committed cells
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14
Q

What are differentiation inducers

A

-Proteins that control differentiation of stem cells into specific blood cell types.
Each differentiation inducer acts on a specific committed stem cell.

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15
Q

Name factors outside the bone marrow that regulate growth and differentiation

A

–Low oxygen levels which increases RBC production
-Infections which stimulates production of specific white blood cells to combat the infection

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16
Q

Name briefly the main stages of RBC formation

A
  • Proerythroblast formation
  • Cell division
    -3 stages of development
  • Condensation of the nucleus and removal of organelles
  • Reticulocyte stage
    -Maturation ino erythrocytes
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17
Q

Explain Proerythroblasts formation

step(1)

A
  • The proerythroblasts are the first identifable cells in the RBC lineage
  • And they orginate from CFU-E stem cells
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18
Q

Explain the cell division process in the formation of RBC

step 2

A
  • Proerythrocytes divide multiple times producing several generations,
  • The first generation is called Basophil erythroblasts
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19
Q

Explain the process that happens in the stages of development

step 3

A
  1. Basophil erythroblats is the first generation , in which its named for its ability to stain with basic dyes
  2. Then the second stage is Polychromatophil erythroblasts, which is wehere hemoglobin synthesis occurs
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20
Q

What stage happens After the 2 stages of development in producing RBC

step 4

A

CONDENSATION OF NUCLEUS AND REMOVAL OF ORGANELLES
- As the cells mature,
-hb concentration increases
-Nucleus condenses into a small size
- And organelles such as ER are reabsorbed

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21
Q

What happens in the reticulocyte stage

step 5

A
  • The cells become a reticulocyte
  • Reticuolcytes contain remnants of organelles and a small amount of basophillic material
  • Then they enter the bloodstream via diapedesis( movement through capillary pores)
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22
Q

Name the 2 stages in the stages of development for production of RBC

A
  • Basophil erythroblasts
    -Polychromatophil erythroblasts
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23
How is a mature erythrocyte formed
- W/n 1-2 days the remaining basophillic material disappers and the cell becomes a mature erythrocyte
24
What is the purpose of red blood cell regulation
- It ensures sufficient red blood cells to transport oxygen to the tisues without impending blood flow
25
Name three stimulis for RBC production
- Anemia -High altitudes -Circulatory diseases
26
What is the role of Erythropoietin and hypoxia
- It is a glycoprotein hormoe that is essential for RBC production under hypoxia - Hypoxia triggers erythropoietin production which stimulates RBC formation until oxygen levels become normal
27
What is the site of Erythropoietin production
- About 90 % in the kidneys, which is secreted by fibroblast-like interstitial cells in the cortex and medulla and the rest in the liver
28
Explain the mechanism of how Erythropoietin causes RBC production
-It stimulates the formation of proerythroblasts from hematopoietic stem cells -Then, its speeds up the progression of the proerythroblasts through the embyonic stages
29
What does the absence of Erythropoietin lead to
- Reduced minimal RNC production
30
What is Vitamin B12 and Folic Acid essential for?
- DNA synthesis, forming thymidine triphosphate
31
What does a deficiency in V12 and Folic acid lead to
Maturation failure Anemia
32
Where is Folic Acid found in
Green vegetables,liver,fruits
33
What disorder is Folic Acid deficiency associated with
- Gastrointestinal absorption disorders like sprue
34
What does deficient erythropoiesis produce
It produces large,irregular RBCs called macrocytes whcih have fragile membranes and shorter life span
35
What causes deficient erythropoiesis
Deficiency on folic acid or V12
36
Where does hemoglobin synthesis begin and continue
- Begins in polychromatophil erythroblasts and continiues into the reticulocyte stage
37
What is the role of retoculocytes in hemoglobin formation
- Synthesize small amounts of hemoglobin 1 day before maturing into erythrocytes
38
Explain the chemical steps in Hb formation
-Succinyl-CoA combines with glycine to form pyrrole. -Four pyrroles form protoporphyrin IX, which binds with iron to create heme -Each heme combines with a polypeptide chain (globin) to form a hemoglobin subunit. -Four subunits combine to form a complete hemoglobin molecule.
39
Name the 4 types of Hb chains
- Alpha -Beta -Gamma -Delta
40
What does adult hemoglobin consist if
2 alpha and 2 beta chains
41
How many heme groups does hb have and its role
- Has 4 heme groups, this allows it to carry 4 ocygen molecules
42
Explain Hb binding to oxygen
- It binds to oxygen loosely and reversibly
43
What is the total amount of iron in the body
- 4-5 g
44
Explain iron distribution in the body
65% in Hb 4% in myoglobin 1% in heme compounds 15-30% is in ferritin
45
How is iron transported
- It binds to apotransferrin in the blood to form transferrin -Transferrin carries iron into the plasms and delivers it to the tossues where it is needed
46
Where is excess iron stored
- Reticuloendothelial cells
47
Name and desribe the 2 ways in which iron is stored
- Ferritin: Main way to store iron - Hemosiderin: Insoluble from of storing iron
48
How is iron recycled
- After 120 days, aged/old RBCs are destroyed and hb is broken down by moncyte-macrophage cells - The iron is released and stored in the ferritin pool -
49
What is Anemia
A deficiency of hemoglobin in the blood, caused by few or insufficient RBCs in the cell
50
Name the types of Anemia
- Blood loss Anemia -Aplastic Anemia -Megaloblastic Anemia -Hemolytic Anemia
51
What is Aplastic Anemia caused by
- Bone marrrow dysfunction often due to Toxic chemicals
52
What is Megaloblastic Anemia caused by
- Caused bye a deficiency in Vitamin B12,folic Acid
53
What is secondary Polycythemia triggered by and what does it cause
Tissue hypoxia due to low oxygen levels - Causes increased RBC
54
What affects does Anemia have on the circulatroy system
- Reduced viscosity -Increased work load on the heart
55
What is polycythemia vera what does it result in
- A pathological condition due to genetic mutation in the blood - uncontrolled RBC production - Leads to excessive WBC and platelets production
56
What are the effects of polycythemia on the circulatroy system
-Increased blood Viscosity -Increased blood volume
57
What is the function of leukocytes
- To combat infection and inflammation
58
Where are the formation sites of Leukocytes and explain what they produce
- Bone Marrow: produces granulocytes,monocytes and lymphocytes -Lymph tissue:produces lymphocytes and plasma cels
59
Name 3 types of leukocytes
- Monocytes -Plasma cells -lymphocyte
60
What is the function of granulocytes and moncytes
- Release inflammatory substances
61
What is the function of platelets
Activate blood clotting
62
Name the two lineages of white blood cells
- Myelocytic lineage -Lymphocytic lineage
63
Desribe the 2 lineages of the WBC and what they produce
-Myelocytic Lineage: Starts with myeloblast and produces granulocytes and monocytes. -Lymphocytic Lineage: Starts with lymphoblast and produces lymphocytes and plasma cells.
64
What are platelets known as
- Thrombocytes
65
What are platelets formed from
Fromed from megakarycoytes fragments in the bone marrow
66
What is the life span of Plasma cells( Thrombocytes)
10 days
67
What is the life span for granulocytes
4-5 days
68
What is the life span for monocytes
10 - 20 hrs
69
What is the role of neutrophils in Defense
Destroy and attack bacteria in the blood streams
70
What are macrophages
Originate as blood monocytes
71
How des neutrophils and monocytes enter the cells
Squeeze through the gaps between the endothelial cells in the capillaries and venules
72
Why do neutrophils and macrophages use Ameboid motion
They use it to travel through the tissue
73
Explain WBC attraction to inflamed areas by chemotaxis and examples of chemicals released
WBCs are directed towards inflamed areas by chemical gradients of substances released during inflammation, including - Bacterial or viral toxins
74
What is phagocytosis
The ingestion of harmful agents by neutrophils and macrophages
75
Name 3 selective mechanism used in allow better phagocytosis
-Surface texture - Protective coats - Opsonization
76
Explain the purpose of surface texture as a selective mechanism in phagocytosis
- Rough surfaces enhances phagocytosis
77
Explain the purpose of protective coats as a selective mechanism for phagocytosis
Substance have protective coating that repel phagocytes , whereas dead tissues or foreign particles do not have these coats making them vulnerable
78
What is the purpose of Opsonization as a selective mechanism in phagocytes
Antibodies and complementary proteins like C3 mark pathogens for phagocytosis
79
Explain the mechanism of Phagocytosis
Mechanism of Phagocytosis: -Neutrophils and macrophages use pseudopodia to surround and engulf particles, forming a phagosome. -The phagosome fuses with lysosomes to create a phagolysosome, where the ingested material is digested.
80
Explain phagocytosis by neutrophils - what are they specialised for
- Nuetroohils are fast acting phagocytes that ingest 3-20 bacteria before dying - they are specialised for small particles like bacteria
81
Explain phagocytosis by macrophages
Phagocytosis by Macrophages: -Macrophages, derived from monocytes, are more powerful and long-lasting than neutrophils. -They can engulf larger particles, such as red blood cells or malarial parasites, and survive after digesting particles.
82
Explain how phagocytized particles are digested
Digestion of Phagocytized Particles: Lysosomes release digestive enzymes into the phagosome to break down the ingested material. Macrophages have additional enzymes, like lipases, for digesting lipid-rich bacterial membranes.
83
How does the neutrophils and macrophages kill bacteria resistant to enzymatic digestion
Neutrophils and macrophages produce bactericidal agents (e.g., superoxide, hydrogen peroxide, hydroxyl ions) that kill bacteria resistant to enzymatic digestion.
84
What happens to the histiocytes in the skin
- Divide locally to combat infections and destroy pathogens
85
What does the reticuloendothelial system include
- Monocytes -Mobile macrophages -Fixed macrophages
86
What is the function of the macrophages in the lymph nodes
- Trap particles from lymph
87
What is the function of the kupffer cells in the liver
- Filter bacteria from portal blood
88
What is the function of the Aveolar macrophages in the lungs
They phagocytize particles in the lungs
89
What is inflammation
- Tissue injury from bacter,chemicals or heat
90
What are3 key features of inflammation
- Tissue swelling -Vasodilation -Clotting
91
What is the purpose of the Walling-of Effect
To block the spread of bacteria by forming fibrin clots
92
What is the first line of defense what is the second line of defense what is the third line of defense
Tissue Macrophages Neutrophils Macrophage invasion
93
What components does Pus contain
- Macrophages -Tissue fluid -Dead neutrophils
94
Name the 3 mechanisms in which neutrophils invade
-Margination -Diapedesis -Chemotaxis
95
What is the primary role of Eosinophils in
Parasite infections
96
What is the function of basophils
- similar to mast cells release seratonin histamine
97
What is the role of basophils in Allergies
-React with igE antibodies release
98
What is Leukopenia
- Low production of WBC by the bone marrow
99
What causes leukopenia
- drugs,radiation
100
What are the treatments for leukopenia
- Antibiotics
101
What is leukemia
- Uncontrolled production of WBX due to cancerous mutation
102
Name the 2 types of leukemia
-lymphocytic leukemia -Myelogenous leukemia
Medicine Sem 1
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