Body Logistics (13-22) Flashcards
multi-potent haemotopoietic stem cells differentiate into
common myeloid and lymph progenitor cells
which hormone stimulates myeloid progenitor cells to differentiate into erythrocytes
erythropoietin
which hormone stimulates myeloid progenitor cells to differentiate into thrombocytes
thrombopoietin
which hormone stimulates myeloid progenitor cells to differentiate into T and B cells
interleukins
which factor stimulates myeloid progenitor cells to differentiate into granulocytes
Granulocyte-colony stimulating factor (G-CSF)
what releases erythropoietin
the kidneys
when do the kidney release erythropoietin
in response to hypoxia –> leading to increased RBC production
haemopoeisis refers to
production ion blood cells in the bone marrows
erythrocytes
carry oxygen bound to haemoglobin (made of two a and two B chains) to respiring tissue
how long to RBC survive
120 days before being broken down by the liver or spleen
neutrophils
multi-lobed nucleus and small granules - travel to site of infection via chemotaxis and perform phagocytosis - cytokines such as G-CSF increase neutrophil production and chemotaxis
eosinophils
bi-lobed nucleus and release cytotoxic enzymes associated with allergic reactions i.e. asthma and hayfever - helminth infections
basophils
have large dark purple granules which contain histamine and heparin
monocytes
large cells with folded nucleus and grey/blue cytoplasm. They mature into macrophages and perform phagocytosis
lymphocytes
can either be T cells (T-helper or T- cytotoxic) or B cells Small cells with large round nucleus
platelets produced from
megakaryocytes in bone marrow - involves clotting cascade
cartilage is a type of
connective tissue
cartilage consists of
chrondorpcytes
outline how chondrocytes are produced
fibroblasts –> chondroblasts –> chondrocytes
chondrocytes are surrounded by
a dense network of type II collagen and elastic fibres embedded in a gel-like matrix
what makes cartilage highly resilient (can bear weight and is flexible)
a dense network of type II collagen and elastic fibres embedded in a gel-like matrix (ground substance)
is cartilage vascular or avascular
avascular
how can cartilage be avascular
the perichondrium surrounding the cartilage can supply the chondrocytes with oxygen and nutrients
can adult cartilage repair itself
no- chondrocytes are fully differentiated- lost nucleus so can’t undergo mitosis
what is cartilage replaced with when damaged
fibrous scar
what is ground substance in cartilage formed of
glycosaminoglycan - hyaluronic acid
hyaluronic acid allows
resistance to compression without affecting flexibility
what covers most cartilage
a connective tissue called perichondrium - it is avasucalr and its vessels supply nutrients to the cartilage and cells (chondrocytes)
name 3 types of cartilage
hyaline elastic fibrous
hyaline cartilage found
- Articulating surfaces (joints) 2. Epiphyseal growth plates 3. Framework for feral development
what is found int he matrix of hyaline cartilage
proteoglycans, hyaluronic acid and type II collagen
how is hyaline cartilage produced
- Fibroblast move from he top to the bottom as they differentiate into chondrocytes (appositional growth) 2. Chdonrocytes at the bottom then deposit further matrix (interstitial growth) 3. cell apoptosis releasing matrix
elastic cartilage
matrix contains more elastic fibres giving it more elasticity
where is elastic cartilage found
1) other ear (pinna) 2) epilgottis 3) eustachian tube
fibrous cartilage cells
made up of chondroblasts and fibroblast - combinations of a dense regular tissue and hyaline cartilage
fibrous cartilage acts as a
shock absorber
fibrous cartilage found
1) Intervertebral discs 2) menisci (knee) 3) pubic symphysis
ways bone is produced
endochondrial ossification intramembranous ossification
where does endochondrial ossification occur
all bones except flat bones
outline endochondrial ossification
1) intake cartilage model 2) collar of periosteal appears in the shaft 3) central cartilage calcifies and nutrient artery penetrates, supplying bone and depositing osteogenic cells. (primary ossification centre formed) 4) Medulla becomes cancellous bone 5) Cartilage forms epiphyseal growth plates 6) epiphyses develop secondary centres of ossification 7) Epiphyses ossify and growth plates continue to move apart, lengthening bone 8) epiphyseal growth plates replaced by bone 9) hyaline articular cartilage persists
draw and label basic structure of bone
endochondral ossification occurs in
all boens except flat bones
osteoblasts
deposit osteoid
osteoclasts
release H+ ions and lysosomal enzymes to resorb bones
osteoblasts stuck in their own matrix
osteocytes
intramembranous ossification occurs in
flat bones
intramembranous ossification process
- mesenchymal stem cells form a tight cluster called a nidus)
- MSC becomes osteoprogenitor cells which then become osteoblast
3) osteoblasts lay down Type 1 collagen (osteoid)
4) osteoid minerlases to form rudimentary bone spicules
5) spicules join to form trabeculae which merge to form cancellosu bone
6) this is replaced by lamellae of mature compact bone
cancellosu bone
formas a network of fine bony columns or plates to combine strengths with lightnesss
- spaces are filled with bone marrow
compact bone
forms the external surfaces of boen and compirse 80% of the bodys skeletal body mass
compact bone is arranged in rings of bone called osteons
- within the osteons are made up lamellae
what runs down the osteon
haversian canal
haversian canal
runs vertically down the osteon- supplying the bone with blood vessels and lymphasti vessels
the volkmanns canal
runs horizontally between osteons
-supplying blood vessels and lymphatics
ar ehaversian and volkmanns canals found in spongy bone
no
cortical bone
same as compact
outline bone fracture repair
- a blood clot (haematoma) forms giving ris eto a pro-callus of granualtion tissue (where fibroblasts release collagen)
- granulation tissue turns into fibrocarilaginous callus in which bony trabeculae develop
- endochondral and itnramembranous ossification give rise to a bony callus of spongy bone
- Cancelleous bone is now remoddels into compact bone in the cortical region (outward)
osteoporosis
a metbaolic disorder where the mass of mienralised bone decrease
- bone can no longer provide mehcnaical support
- loss of trabecular bone is what icnreases suceptibility to fracture
trabecular bone
also called cancellous bone, is porous bone composed of trabeculated bone tissue. It can be found at the ends of long bones like the femur, where the bone is actually not solid but is full of holes connected by thin rods and plates of bone tissue
osteoporosis occurs due to
- excessive bone reabsorption (increased osteoclast function)
- Decreeased boen formation (decreased osetoblast function)
how many types of osteoprosis
2- primary (2) and secondary (1)
type 1 primary osteoporosis occurs
in post-menopausal woemn
- due to increase in osteoclast number, a result of oestrogen withdrawal
type 2 primary osteoporosis
occurs in elderly people of both genders (senile osteoporosis)
- ocurs due to decreased osteoblast function
risk factors for osteoporosis
Genetic: peak bone mass higher in afro caribbean than caucasian and asians
Insuficicnet callcium itnake
Insufficient vitamin D
Exercise (immobiliasation)
Smoking
reocmmended calcium intake per day
800mg/ day
insufficient vitamin D itnkae due to
renal failure or inadequate exposure to sunlight
Where is the most fluid pushed out of the capilalry
at the ateriol end due to hight hydrostatic pressure
when gluid is pushed out of the capillary it becomes
interstitual fluid
when and why does intenristial fluid move back into the capillaries
at the venule end due to low hydrostatic pressur ena dhigh onctoic pressure (e.g. plasma protien albumin)
what happens tot he remaianing intersitila fluid that is nopt reabsorbed back into the capilalry at the evnule end
drains into lymphatic vessels which run alongside capillaries
walls of lymphatic vessels contains …
mslal flaps whcih opens when pressure increases e.g. when itnerisital fluid is building up
–> allows the excess intersitial fluid to move into the lympahtic vessel and be drained
lymph is pushed …… gravity by ….. and …..
agaisnt gravity by muscles or arterial pulsation
what prvent backflow of lymph
valves (like veins)
the right lymphatic duct
draisn lumph fromt he right arm and upper right part of the torso intot he internal jugular vein
the alrge thoracic duct
takes lymph from the rest of the body and drains into the subclavian vein
lymoh nodes ahve a similar shape to
kidneys
describe how lumph enters lymph nodes
- lymph enters lymph nodes via afferent lymphatic vessels found ont he convex surface
- Lymph leaves the nodes through afferent lymphatic vessels which exit the hilum (concave)
where are the gemrianl centres from and what do they contain
on the outer regions of the node
-cotnained follicular dendiritc cells which are invovled in antigen presentationa nd activation of B cells
the spleen
largerst lympahtic organ with rich blood supply (v red)
spleen 2 main functions
1) Immune fucntion- includes antigen presentation by APCs and proliferation of B and T cells
2) Haematopoietic function- includes destruction of old RBCs anf retrieval of iron from Hb
what happens to the spleen inr esponse to systemic infectiosn and when do lymph nodes enlarge
the spleen enlarges in response to systmeic infections e.g. malaria
Lymph nodes enlarge in repsosne to localised infection
the thymus sits
infront of the heart and behind the sternum ontop of the trachea
the thymus is involved in the
maturation of T cells - THMIC CELL EDUCTION
the thymus is fully functional at birth but turns into ….
fat by early teens
summarise the immune response
1) first line of defence is macrophage sna dneutrophils
2) they destory pathogens via phagocytosis
3) if these fail they present antigens on their surface and revael to lumph nodes as APCs
4) activation of humal immunity (B cells differntiate to plasma cells and secrete specufuc antibodies)
5) Acitvation oc cell emdiated imunity (acitvates T kills cells, T helper cell and T memory cells
oedema is the
accumulation of excess watery fluids in cell tissues or serous cavities
if lymphartic vessels or lymphn nodes are obstrucuted
can lead to an accumulation of lymph- lymphoedema
lymoh is
protien rich and fibroblast proliferation causes this fluid to harden–> making swelling non pitting
which type of cause of oedma leads to pitting swelling
heart failure- low protein contnet
the two arms of a nervous system
CNS and PNS
parts of the CNS
braina and spinal cord 9connects brain and peripheral NS)
PNS made up of
somatic and autonomic
somatic NS
controls voluntary muscles and transmits information to the CNS
- all nAchR
autonomic nervous system
controls involuntary body functions such as heart rate
autonomic ns made up of
parasympathetic and sympathetic NS
sympathetic nervous ssytem
arouses body to expend energy
parasdympathetic nervous system
calms body to consevre and maintaine energy
brain matetr made up of
white and grey matetr
grey matter in the brain
found on the outside of the brain
- houses the cell bodies of neurones
- where processing of info occurs
white matter in the brain
found on the inside of the brain
- mainly formed of axon (myelin sheath around neuroens gives it the white colour)
how many spinal nerves
31
spinal nerves split into
a dorsal root and ventral root
- Sensory nerves enter the cord via the dorsal root
- motor nerves leave the cord via the ventral root
sensory enuroens carry impleses
from receptors in the greay matter via the dorsal horn
cell bodies of snesory enuroens are found in the
dorsal root ganglion
motor neuroens carry impuleses to
effectors e.g. muscles
cell bodies of motor neurones are found in
grey matter
what type of cells are sneosry neuroens
pseudounipolar cells
- axons come out of the cell body and splits into ttow branches- one tot he CNS and the other into the PNS
strucutre of spinal nerve
- spinal nerve is surroudn ed by a alyer called the pineruium
- the neurones are further arranged into fasicles (separated by perineum)
- both myelinated and unmyelinated neurons found in the fasicles
- myelinated fibres are separated from unmeylinated firbes by endoneurium
myelinated fibres are
separated from unmeylinated firbes by endoneurium
what surorunds spinal nerves (collection of neurones)
epineurium
fasdicles of neuroens are separated by the
perineurium
name 4 support cells of the NS
- Schwann cells
- Oligodendrocytes
- astorcytes
- microglia
schwann cells
a type of glial cell.
Wraps around the axon and the phopsholipid membrane acting as an electrical insulator
some schwanna cells only provide structural support and do not myelinate neurones
oligodendrites
can myelinate several axons at the same time
- electircal isnulator of brain neurones
Structurally simialr to schwanna cells
astorcytes
form tight junctions with capilalry endotheluial cells in order to rpevent leaking across the BBB
- they can move excess NT from synapse
microglia can
phagocytose foreign bodies in order to get rid of them
give the broad structure of the skin
Epidermis (outside)
Dermal layer (inside)
Hypodermis (connective tissue layer)
epidermis
function: synthesis of keratin, prevent water loss and entry of pathogens
4/5 layers if cells
no blood vessels
some terminal enrve endinigns
dermal layer (dermis)
between epidermis and hypodermis
Function:
- contains hair and sweat glands - thermoregulation
- sensory strucutres- touch (pacinian corpuscle)
- gives structure of skin and so body shape
3 layers
3 layers of the dermis
- papillary- upper
- reticular- lower
- dermal papillae - interdigitating
signs of inflammation (4)
- Rubor
- Dolor
- Calor
- Tumor
rubor
redness
dolor
pain
calor
warmth
tumor
swelling
why do sites become inflammed
- vasodilation- causes rubor and dolor
- increased vascular permeability - causes production of protein-rich exudare leading to tumor
- influx of leukocytes
the stratum corneum is
the otuermost layer of the epidermis and made out of keratinsed cells
psoriasis
involves desquamation 9sheddign) of this layer
- due to hyperproliferation of the keratinocytes
- transdit time is 2-3 days
- increases infiliration of leukocytes
