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Hematolymphatic
System/Anatomy
BLOOD: INTRODUCTION
• The blood is formed of cells and fluid called plasma.
• Cells: RBCs (erythrocytes), WBCs (leucocytes) and Platelets
(thrombocytes).
• The plasma contain many substances such as nutrition,
proteins hormones, minerals (Na, K, Ca and others).
• When we remove coagulation factors removes from the
plasma it became serum. So, serum is plasma without clotting
factors such as fibrinogen
Plasma Proteins and their functions
• Albumin: maintains osmotic pressure +
• Globulin: transport vitamins, lipids, iron +
• Clotting proteins: examples; prothrombin and
fibrinogen
• Complement proteins: kill microbes and
initiate inflammation
• Other proteins
Cells:All cells are formed within the
bone marrow
WBCs are biconcave Discs
WBCs: Granulated (neutrophiles, eosinophiles and basophil) and
non-granulated (monocytes and lymphocytes.
Platelets: the smallest blood cells
What you should know about cells
•
•
•
•
•
•
Shape
Size
Structure
Number (ratio)
Function
Features and identification
RBCs: About 43% of the blood volume
• Shape: Biconcave disks
• Diameter: about 7.5 um with thickness 2um at
peripheral and < 1 um in the center.
• Number: 5 millions/cubic mm in male and 4.5
cubic millions in female
• Structure: In human; RBCs have no nuclei or
organelles. They are filled with Hemoglobin. Also,
they contain enzymes such as carbonic anhydrase
• Function: main function is to carry O2.
• RBCs: life about 120 days and old cells destroyed
by spleen
RBCs: Scanning EM
RBCs: Light Microscope (LM)
WBCs
• About 1% of the blood volume and form then
layer between the RBCs and the blood plasma
on centrifugation called Buffy coat
• Classified based on whether they contain
specific granules or not into:
• Granuloctes (neutrophiles, eosinophiles and
basophil) and
• Non-granulocytes (monocytes and
lymphocytes).
WBCs
Features
Neutrophils Eosinophils
Basophils
Lymphocytes Monocytes
Numb/
Ratio
3500-7000
60-70%
150-400
2-4%
50-100
<1%
1500-2500
20-25%
200-800
3-8%
Diameter/ 8-9
um
9-11
7-8
7-8
10-12
Nucleus
3-5 lobules
2 lobules
S-shape
round
Kidney shape
Specific
granules
+ Fine
-
-
Life span
<1 week
<2 weeks
1-2 years
Months to
Years
Days in blood
Months in CT
Function
Kill bacteris
Kill
parasites
Histamine
Heparin +..
Immune
response
Give
Macrophage
+ Medium + Large
LM/ Neutrophils:
Barr body (sex chromosome): drumstick structure attached to the neutrophils nuclei and contains X chromosome in females
LM/ Neutrophils
LM/ Neutrophils
LM/ Eosinophils
LM/ Basophil
•
LM/ Monocyte
LM/ Monocyte
Lymphocytes: B and T lymphocytes
LM/ Plasma cells
Platelets or thrombocytes
• The plateletes are small (2-4 um) non-nucleated fragments of large cells in
the bone marrow called megakaryocytes
• Number:250000-400000/cubic mm and live less that 14 days
• It is formed of peripheral clear (light) zone called hyalomere and central
darker region called granulomere.
• Hyalomere contains: 1-10-15 parallel microtubules and actin and myocin
that can form contractile apparatus and 2-two tubular systems (surface
and dense tubular systems). The lumen of the surface coiled tubular
system one outside and therefore increase the syrface area of the
platellets 7-8 times.
• Granulomere: contains three types of granules (alpha, delta and lambda
(the lambda are lysosomes), some mitochondria, peroxisomes, glycogen
and enzymes.
• Function: the platelets limit hemorrhage (bleeding).
Platelets:LM & TEM
LM/Identify these cells
LM/ Identify these cells
LM/Identify these cells
SEM:RBC, WBC and platellet
Identify/TEM
Hempoisies: formation of blood cells
• About 100 bilion BCs produced daily with our BM to replace
the BCs that die or leave the circulation
• Pahses: 1-mesoblastic in the YS in the 3rd weeks of the
prenatal life…..>nucleated erythrocytes. 2-Hepaticby 6th week
of the prenatal life …..>nucleated erythrocytes. 3-Splenic
begins during the second trimester …..>nucleated
erythrocytes,4-myeloid start in the 5th month to the end of life
of the prenatal life …..>non-nucleated erythrocytes
Sites of Hemopoiesis
Hemopoiesis:Growth Factors
Hemopoiesis:Stem cell...>Progenitor
cells....>Precursor cells...>BCs
ERYTHROPOIESIS
ERYTHROPOIESIS
• The precursor cells called Proerythroblast….>
• Basophilic erythroblast….> Polychromatophilic
erythroblast….>Orthochromatophilic
erythroblast….>Reticulocytes….>Erythrocytes
• Size decrease from 14-19um to 7-8um
• Nucleus decrease in size then leave the
Orthochromatophilic erythroblasts (normoblast) and
become reticulocytes that leave bone marrow to become
mature in the circulation (erythrocytes).
• Cytoplasm:blue…>yellow-pink in blue background in
Polychromatophilic erythroblast….>pink in blue
background……>pink in reticulocytes and erythrocytes.
Bone Marrow
• The only site of hemopoiesis after birth
• Structure: The BM background is reticular CT with reticular
fibers and reticular cells. Within this tissue, there are large
blood capillaries (sinusoids) between arterioles and venules.
Between these sinusoids, there are islands of hemopoiesis
cells which include stem cells, progenitor cells, precursor cells
and different types of blood cells in different stages of
development. Also, there are macrophages (nurse cells) in the
BM which remove nuclei of erythroblasts, bring hem (iron) for
the developing RBCs, remove deformed cells and help
development and maturation of some types of blood cells
• Types: Red BM (more active) and Yellow BM. In Babies, all of
the BM is Red. At age 20 years, the BM of diaphysis of long
bones become yellow MB because the reticulocytes store fat.
Bone Marrow: Structure
RBM and YBM: at age 20, BM in
diaphysis become yellow BM
LYMPHATIC (IMMUNE) SYSTEM:
INTRODUCTION
• Lymph
• Lymphatics
• Lymphatic tissue
Lymph:extra amount of intercellular
fluid that enter lymphatic capillaries
Lymphatic vessels:left lymphatic duct
(thoracic duct) and right lymphatic duct
Body parts drained by left lymphatic duct
(thoracic duct) and right lymphatic duct
Lymph capillaries similar to blood capillaries but
thinner while the lymph vessels are similar to the
veins with valves but thinner
Lymphoid Tissue
• Diffuse lymphatic tissue : lymphocytes: free or
organized in lymph follicles (nodules).
• Aggregated lymphatic tissue :
1.Capsulated ( surrounded by dense irregular CT
capsule that send trabeculae C.T capsule ) : ,
lymph nodes , spleen and thymus . The
background of these organs are formed of
reticular CT.
2. Partially capsulated : tonsils
3.Non-capsulated : peyer’s patches .
Lines of body defence
• A-Physical barriers exs: skin and MM
• B-Immune system which is classified into two
systems:
• 1-Innate immune system and
• 2-Adaptive immune system
The Innate Immune System
• Features: 1-natural, 2-rapid and with no
immunological memory and 3-non-specific.
• Components:
• A- Cells: 1-Neutrophiles, 2-Macrophages and
3-Natural killer cells (NKCs).
• B-Chemicals:1-complements,2-antimicrobial
peptides and cytokines of different types.
Cells of the Innate Immune System
• -Neutrophiles: Kill bacteria
• -Macrophages: They act as antigen presenting cells, have
receptors for antibodies and release colony-stimulating
factors (CSF): G-CSF and GM-CSF that stimulate the
formation and releasing of neutrophiles.
• NKCs: Kill tumor cells, virally infected cells, bacteria and
parasites. They have receptors for antibodies that mediate
their cytotoxicity (antibody-dependent cellular
cytotoxicity), also they have both killer-activating
receptors and killer-inhibitory receptors. The killerinhibitory receptors recognize MHC I (major
histocompatibility complex type I) that are located in the
plasma membrane of healthy cells, So, the NKCs recognize
the healthy cells and do not kill them
Notes on cells of the Innate Immune
System
• 1- The NKCs recognize MHC I (major histocompatibility complex
type I) of healthy cells, So, they do not kill them. But these MHC I
are necessary for another killer cells (T Killer or T cytotoxic
lymphocytes). This make these T lymphocytes unable to recognize
and kill tumor and virally infected cells which suppress (inhibit) the
production of MHC I. However, this maneuver by the tumor and
virally infected cells make then targets to the NKCs.
• 2-The cells of the innate immune system depend on ToLL-like
receptors to initiate their inflammatory and immune responses.
The ToLL-lke receptors are of different types and locations (both
intracellular and parts of the plasma membrane (see page 275).
Chemicals of the innate immune
system
• 1-complements: blood proteins that can kill
microbes by damaging their plasma membrane
• 2-antimicrobial peptides: ex: defensins that
produces by epithelial cells and can kill gramnegative bacteria
• 3-cytokines: there are different cytokines released
by various cells of both innate and adaptive immune
systems. Exs:1-interleukins released by lymphocytes,
2-interferons have antiviral activity, 3-colonystimulating factors (CSF) that stimulate production
of blood cells (hemopoeisis) and 4-chemokines that
attract WBCs to sites of inflammation.
Adaptive immune system
• A-features: acquired, have immune memory,
specific and have self/nonself recognition
• Components: 1-B lymphocytes, 2-T
lymphocytes and 3-antigen presenting cells
(macrophages)
B and T lymphcytes
• B lymphcytes: activated by antigen (microbes)
and start mitosis and differentiate into: 1-B
memory cells and 2-plasma cells.....>antibodies
(humorally mediated immune response).
Immunogloblins types:IgM, IgA, IgG, IgD and IgE.
• T lymphocytes enter thymus as immature cells,
then leave the thymus after programmed as
immunologically competent cells called naive
cells which when activated by tumor or microbes
(bacteria, virus) they divide by mitosis and
differentiate into: 1-memory cells and 2-effector
cells (T-helper cells, Cytotoxic T-lymphocytes/T
killer cells......>cellularly mediated immune
response and T-regulatory cells)
Capsulated lymphatic tissue :Lymph
Nodes
Lymph drainage from different parts of
the body
Lymph Nodes
• Ovale or kidney shape organs with convex and concave surfaces
with hilum with diameter normally less than 3 cm.
• Distribution:widespread especially in the neck, axilla, groin and
along the large blood vessels.
• It is surrounded by CT capsule that send trabeculae with
subcabsular sinus and paratrabecular sinuses.
• It is formed of 1-cortex with lymphoid follicles (nodules)/B lymphocytes and plasma cells,2-paracortex/T-lymphocytes and
medulla with medullary cords (B-lymphocytes, plasma cells and
macrophages) and medullary sinuses (filled with lymph).
• Lymph circulation: lymph enter through affarrent lymphatics…….>
subcabsular sinus………>paratrabecular sinuses…….>efferent
lymphatics. The lymph nodes filtrate lymph and become large and
hard in cases of infection or tumor.
Lymph Nodes: Main parts
Lymph Nodes:Cross section
It’s coverd by capsule
(capsulated) wihch invades the
tissue but without separating it
into lobes.
- In the lymph node you have
two areas, cortex which is
darker in color, and the
medulla.
- The lymph nodules are all
found in the cortex.
- The medulla is composed of:
medullary cord and sinuses.
Lymph Nodes: Cortex and Medulla
Lymph Nodes: Lymphoid Follicles
Zones of the Germinal Centers:
• Central dark zone formed of centroblasts……>
basal light zone formed of centrocytes with
switch immunoglobulins (sIgs)…….>light apical
zone to become either B memory
lymphocytes or plasma cells
Capsulated lymphatic tissue : Spleen
The spleen
• Remember this rule about the spleen:1x3x5 (dimentions in
inchesx7 (weight in oz, in grams=150-200)x9x11(related left ribs).
• Surfaces, borders and relations: 1-diaphragmatic (smooth and
convex and directed upward, backward and laterally) the spleen is
related to the diahphragm which separate it from the left 9-11 ribs
and left lung and plura 2-visceral with gastric (directed forward
upward and to the right and located behined the stomach) and
renal (posteriorly) parts.concave with hilum. Also, this surface
related to the tail of pancrease and colon. The spleen has anterior
and posterior borders.
• Supplied mainley by the splenic artery/branch of the celiac trunck
and drained by splenic vein (part of the portal venus system)
• Functions: 1-remove old RBCs (Red Bulbs), 2-part of our immune
system (White Bulbs), 3-other functions such as RBCs production in
embryo and production of lymphocytes.
• It has only efferent (with no afferents) lymphatics
• The spleen developed from mesoderm (from and within the dorsal
mesentery).
Spleen: cross section shows White
Pulps and Red Pulps
- It’s covered by connective
tissue capsule that send
trabeculae.
- The spleen is formed of red
pulps and white pulps.
-The red pulps and white pulps
are scattered everywhere in the
organ.
--The white pulps are formed of
nodules (Malpighian
nodules)/B-lymphocytes and
periarteriolar lymphatic sheath
(PALS)/T-lymphocytes while the
red pulps are formed of splenic
sinuses (filled with blood)and
splenic cords (lymphocytes,
macrophages)
Spleen
Spleen: closed and open circulation
Spleen: White Pulp
Spleen: White pulb
Capsulated lymphatic tissue : Thymus
Thymus:location, development,blood
supply and hormones
• It is located in the superior mediastinum just behind the manubrium. It
may exten upward to reach the thyroid gland and downward to the
anterior medistinum. It is large in children then start to decrease with age
so, in old people it is replaced by almost fat tissue.
• It is arise from the third pharyngeal pouch high in the neck then descends
down to its normal position in the superior mediastinum. Tissue of the
thymus gland may be found along its descending path or even embedded
in the thyroid gland.
• It is supplied by the internal thoracic a. and drained into the
brachiocephalic vein and the internal thoracic vein.
• It release hormones like thymopoietin, thymoycin and thymonolin to
control development and maturation of T-lymphcytes
• Like the spleen, the thymus has efferents but not afferents lymphatics.
Thymus: cross section
The thymus is also capsulated
organ.
- There is no lymphatic nodules in
the thymus.
- it’s divided by the connective
tissue into completely separated
lobes.
- You can identify the cortex (dark
zone) and the medulla (light zone) in
the thymus in each lobe.
Thymus: Cross section
* Each lobule has an
outer, darker staining
cortex and an inner,
paler staining medulla.
Cortex of thymus: Cell Types
• A-T-Lymphcytes (Thymocytes)
• B-Epithelial reticular cells: three types: Types I
separate the cortex from the CT capsule and trabculae
and from BV with tight junctions between them, Type
II located in the midcortex with long, wide sheath-like
processes with desmosomes between them to divide
cortex into compartents, Type III located in the center
with long, wide sheath-like processes to form
compartments and also located close to the medulla
with tight junvtions to isolate cortex from the medulla
Medulla of the thymus: Cell Types
• A-T-Lymphcytes (Thymocytes)
• B-Epithelial reticular cells: three types: Types IV
located close to the cortex, Type V located in the
middle of the medulla, Type VI large pale stained
cell that………….>Hassale’s corpuscles that
increase with age
• NOTE:the cortex is formed of more Tlymphocytes and less Epithelial reticular cells, So
it has dense (blue) stain while the medulla is
formed of more Epithelial reticular cells and less
T-lymphocytes, So it has light stain
Thymus: Hassall’s corpuscles
Thymic corpuscle
Thymus: Development and Location
Partially capsulated (Tonsils) :
• They belong to Mucosal Associated
Lymphoid Tisse (MALT) but considered
organs because they are partially
encapsulated.
• Tonsils are covered by epithelium.
• They include:
- Palatine tonsils
- Pharyngeal tonsils
- Lingual tonsils.
Palatine Tonsil
it’s partially capsulated
tissue and partially covered
by epithelium ⇒ Tonsil.
-The noncapsulated surface
is covered by stratified
sqaumous epithelium.
- The most important
identification mark is the
crypts .. If you have
multiple crypts which are
very deep ⇒ Palatine
tonsil.
Lingual Tonsil
Tonsil which covered by stratified
squamous epithelium without deep
crypts ⇒ Lingual tonsil.
Pharyngeal Tonsil
Tonsil that has nodules and
covered by psedostratified
squamous epithelium
(respiratory epithelium) ⇒
Pharyngeal tonsil
Mucosa-associated lymphoid tissue (MALT) :
Diffuse or non-capsulated aggregated
-Within the lamina propria of the mucosa of:
the respiratory, gastrointestinal, urinary and
reproductive tracts.
- It is formed of diffuse lymphocytes or
lymphocytes organized in follicles or both
-At some location it is formed of many follicles
in this case we can give them names:
example; the Peyer’s patches of the ilium.
Lymphoid follicles or nodules: Primary and secondary. The secondary GC
stained light because its cells are large with large cytoplasm and small nuclei
while the peripheral part stained dark and called mantle or corona. The can
be present in all types of lymphoid tissue (diffuse and aggregated, except the
thymus)