Transcript Document

Kharkov National
Medical University
LECTURE for dentistry students
Department of
Histology, cytology and
embryology
Immune system = hemopoietic
Functions:

Production of immune cells (and rbc)

Immune defense
Organs

Central:
red bone marrow, thymus

peripheral:
lymph nodes, tonsils, spleen
Secondary organs
LYMPHOID SYSTEM I
Tonsils of Waldeyer’s Ring
Primary lymphoid
organs - Marrow M
& Thymus T
R
M
A
T
cvl
Lymph nodes -
Solitary nodules
Peyer’s patch
- - - -
- U
o
V Appendix
-
cervical, axillary,
inguinal,
mesenteric, etc
Spleen
Lymphocyte
circulation via
blood vessels and
lymphatics
Red Bone Marrow

Functions: 1. formation of all blood cells,
except T-lymphocytes
2. contains CFU – blood stem cell
Structure: -- basic – reticular tissue,
-- sinuses (wide capillaries),
-- cords of hemopoietic cells
Thymus




Functions:
1. production of T-lymphocytes independent
/they become antigendependent
in the peripheral organs/
2. production of hormones (thymopoietin,
thymosins)

to promote development and action of T lymphocytes
Thymus

Capsule gives off trabeculae, divide
parenchyma into lobules with cortex and
medulla

Reticular epithelial cells – basis of lobules



secrete hormones
Very large in fetus; after age 14 begins
aging involution
in elderly mostly fatty and fibrous tissue
Histology of Thymus
THYMUS young
Cortex - dark
Connective
tissue
Lobules
Medulla light
Hassall’s thymic
corpuscle
round, red, flattened
epithelial cells. Their amount
increases with age
Packed lymphocytes
(thymocytes)
Lymph Node

Functions: production of B-lymphocytes,
filtration of lymph flows through sinuses

STRUCTURE:
Cortex contains lymphatic nodules with stroma
(reticular CT) and lymphocytes

Paracortical zone contains T-lympocytes


Medulla consists of medullary cords of plasmocytes –
lymphocytes, producing antigens

Basic are reticular cells = macrophages
phagocytize
foreign matter
 lymphocytes
 lymphatic
centers
respond to antigens
nodules contain germinal
for B cells activation
Lymph
Node
Fig. 21.12 a and b
Sinuses
for
lymph
flow
Lymph Node
Tonsils

Functions: 1.
production of Blymphocytes,
2. immune defense
Tonsils

Location – folds of mucous membrane of the
oral and pharyngeal cavities

Multiple groups of large lymphatic nodules

Palatine tonsils

Pharyngeal tonsil

Lingual tonsils
Tonsil


Covered by stratified epithelium
Pathogens get into tonsillar crypts and encounter
lymphocytes
Spleen

Parenchyma contains:



red pulp: sinuses filled with erythrocytes
white pulp = lymphatic nodules: lymphocytes,
macrophages; surrounds small branches of splenic
artery
Functions




B-lymphocytes production
blood storage
RBC distruction
immune reactions: filters blood, detects antigens
Spleen
Lymph Nodules in the GIT -
PROTECTION
Endocrine System
is the
second regulating
system
 Produces
blood
hormones to the
 Regulates
growth, metabolism
Classification
 CENTRAL
organs :
hypothalamus, hypophysis,
epiphysis
 PERIFERAL : thyroid,
parathyroid,
adrenal glands.
In some organs the
endocrine tissue constitutes
part of them :
 the
pancreas,
 the ovaries and the testes.
Individual endocrine cells
are found in a variety of
organs, e.g. the GIT and
the kidneys.
Hypothalamus
 Part
of the CNS
 Contains Nuclei of
neurosecretory cells
 anterior(1)
 intermediate(2),
 posterior(3)
H.-1
 Supraoptic
nucleus produces
vasopressin (antidiuretic hormone
– ADH) increases reabsorbtion of
water in kidney.
 Paraventricular
nucleus produces
oxytocin - contraction of muscle
of the uterus during parturition
H.-2
 Releasing
factors - liberins
(stimulate) and statins (inhibit)
for tropic hormones of the
adenohypophysis
3
2
1
Hypothala
Hypophysi
H.-3
 contains
nerve cells,
innervating endocrine
glands
(Hypophysis) Pituitary
Gland
 The
pituitary gland
is attached to the
brain by the
infundibulum 1
 locates under
the hypothalamus
Pituitary Gland
2 Parts:


i
neurohypophysis
adenohypophysis
(d.- pars distalis,
i. - pars
intermedia).
d
n
a
Pars distalis
acidophil cells
 basophil cells.

Acidophils cells

1.
somatotrophs
(produce growth
hormone (GH or
somatotropin)

2.
mammotrophs
secrete prolactin
(LH).
Basophil cells

1. Thyrotrophs
produce thyroid
stimulating
hormone (TSH or
thyrotropin).
Basophil cells



2. Gonadotrophs produce
follicle stimulating hormone
(FSH) regulates ovogenesis,
spermatogenesis
luteinizing hormone (LH)
stimulates
production
of
testosterone by Leydig cells in
males,
formation of corpus luteum in
females.
Basophil cells

3. Corticotrophs
secrete
adrenocorticotropic
hormone (ACTH)
Pars intermedia
produces melanocytostimulating
hormone and
 lipotropic hormone

Neurohypophysis
 Cells
are
pituicytes
 Hering’s bodies
– ends of
axons, contain
hormones of
hypothalamus
Development


Neurohypophysis develops from the
floor of third brain ventricle.
Adenohypophysis develops from an
ectodermal diverticulum - Rathke’s pouch,
that grows upwards from the roof of the
stomatodaeum.
Epiphysis or PINEAL BODY
Epiphysis or PINEAL
BODY
contains two basic
types of the
cells:
 1 – pinealocytes;

2 – interstitial
cells (glial cells)
Epiphysis or PINEAL BODY
controls all
cyclic
processes in
human
organism
Hormones of the thyroid
gland

thyroxin, or
tetraiodothyronin,
T4,

triidothyronin –
T3,

calcitonin
 T4
and T3 regulate
carbohydrate, lipid
and protein metabolism
 calcitonin
lowers blood
calcium level
consists of
follicles,
 lined by cuboidal
epithelium
 The follicle cavity
is filled with
colloid =

thyroglobulin –
complex of
hormones
 Between
follicles
there are
parafollicular
cells
 (or C-cells),
produce
calcitonin
TSH of hypophysis stimulates
T3,T4 production!
PARATHYROID GLAND
 chief
or
principal cells
and
 oxyphil cells.
 Its
Parathormone (PTH)
increases the blood calcium
level by stimulating bone
resorption

is not under control of
hypophysis
ADRENAL (suprarenal)
GLANDS
consist of :
an outer cortex
and
an inner medulla


Cortexepithelial cords:
zona glomerulosa
zona fasciculata
 zona reticularis


Medulla
Hormones:



zona glomerulosa -mineralocorticoids – Na,Ca
homeostasis and water balance
zona fasciculata glucocorticoids – carbohydrat
metabolism
zona reticularis - sex hormones

zona fasciculata and zona
reticularis are under control of
ACTH of hypophysis
Medulla
 Consists
of sympathetic neurons –
chromaffin cells
 produse:
 adrenaline and
 noradrenaline
 -- stress hormones