Anatomy theme 1 Flashcards
What is fascia ?
an internal connective tissue that forms sheets , surrounds and supports muscles , vessels and nerves.
What are the functions of fascia ?
maintenance of shape of muscles - sternocleidomastoid
Compartmentalise and isolate structures of the neck
Separation of movements - prevertebral fascia allows separation of contraction and swallowing
Pathways for neurovascular bundles
retention bands
Where does superficial cervical fascia lie and what does it do ?
between the dermis and the deep cervical fascia
provides neurovascular supply to the skin
What is the function of deep cervical fascia ?
forms a connective tissue sheath - carotid sheath
separate muscle groups based on their function
acts as an extension to bone - increase surface area for attachment
What is the investing layer of deep cervical fascia ?
most superficial of the deep cervical fascia
What does the investing layer of deep cervical fascia do ?
surrounds all the structures in the neck
splits into 2 to surround the trapezius and sternocleidomastoid
What does the pretracheal fascia do ?
most anterior
encloses the thyroid gland , oesophagus and trachea
What does the prevertebral fascia do?
encloses the vertebra and all the muscles of the floor of the post triangle of the neck
What is the clinical relevance of fascia ?
the neck fascia compartmentalises structures in the neck - limit spread of infection
spaces between the layers of fascia - allow infection to develop
What is the structure of bone ?
thick and compact bone surrounds a meshwork of cancellous bone made of individual trabeculae
What is the ECM of the bone reinforced with ?
calcium hydroxyapatite
What are the functions of bone ?
act as levers
protection of internal organs
calcium and phosphorus store
What is the axial skeleton ?
skull
vertebral column
ribs
sternum
What is the appendicular skeleton ?
upper and lower limbs
What is the function of a ligament ?
it prevents excess movement at a joint - keeping hte joint and bones stable
What is meant by taught at max stability ?
there are one set of ligaments open when the joint is open
another set of ligaments closed when the joint is closed
What is a joint ?
union between 2 or more bones
What are synovial joints ?
freely movable
What do synovial joints consist of ?
synovial cavity filled with synovial fluid that is retained by the capsule
capsule thickened to form intrinsic ligaments
What are immovable joints and why are they immovable ?
sutures (eg the coronal suture between the frontal bone and the parietal bones)
synchondroses
Gomphoses
they are immovable because they have a solid plate of cartilage between them
What is a gomphosis ?
peg and socket
eg. between the roots of the maxillary and mandibular teeth and the alveolar processes - this is kept in place by the periodontal ligament
What are partially movable joints ?
syndesmosis and symphysis
What does a symphysis consist of ?
opposing bony surfaces covered in cartilage
separated by intervening fibrous tissue - annulus fibrosis
What does skeletal muscle consist of ?
a fleshy and a tendinous portion
What does the fleshy portion of skeletal muscle consist of ?
muscle fibres
elongated muscle cells - multinucleated , have a sarcoplasm and a sarcolemma
What does the endomysium surround ?
a single muscle cell
What does the perimysium surround ?
several fibres
What does the epimysium surround ?
surrounds fibres overall - the sheets allow for nerves and blood vessels to run
What does the tendinous portion consist of ?
extensions of fibrous connective tissue that attach muscle to bone
What is the proximal end of a muscle called ?
the origin - this is the fixed attachment
What is the distal end of the muscle called ?
the insertion
What happens to the origin and insertion during movement ?
the insertion moves towards the origin
the origin and the insertion are interchangable
How are the muscle fibres arranged in a strap muscle ?
muscle fibres arranged in parallel
How are the muscle fibres arranged in a fusiform muscle ?
large number of fibres that converge on a tendon (like the typical muscle)
What is the structure of a digastric muscle ?
two fleshy bellies joined by a tendon
How are the fibres arranged in a bipennate muscle ?
the fibres insert into the tendons in a leaf shape
even though the fibres are shorter this arrangement allows for powerful contractions.
What are isotonic contractions ?
they allow for actual movement around the joint
What are isometric contractions ?
contraction that provides no movement - eg. tensing
What is the agonist/prime mover ?
muscle producing the intended course of action
What does the antagonist so ?
any muscle that would oppose the intended course of action
When do muscles act as fixators ?
when both muscles are acting
no movement around the joint
the joint is stabilised
What do synergists do ?
the agonist usually produces unwanted movement due to joint complexity this movement is opposed by the action of synergists
What is smooth muscle ?
found in viscera
lacks striations
usually under autonomic control
What is cardiac muscle ?
in the heart only
has striations
cant be tetanised
under autonomic control
What is the exception in the bladder ?
the bladder is composed of smooth muscle but is under voluntary control
What types of contraction do skeletal muscle provide ?
powerful
rapid
fatigued easily
What types of contraction does smooth muscle provide ?
slow
not easily fatigued
sustained
How does the liver have a double blood supply ?
digested products for metabolism are brought by the portal vein - from the GI tract
the hepatic artery provides oxygenated blood
What are the 2 pumps of the heart ?
systemic
pulmonary
How does the heart ensure that the outputs on both sides are matched ?
if the left side pumps more this will enter on the right side and therefore the right side will contract more- outputs are matched
What connects an atrium to a ventricle ?
the atrioventricular orifice
guarded by the atrioventricular valve
What are the 3 layers of a blood vessel ?
endothelial layer
the smooth muscle layer
the elastic layer
What are muscular arterioles ?
resistance vessels
end in precapillary sphincters
resistance to the systemic blood flow
What do capillary walls consist of ?
layer of endothelial cells
What do capillary fenestrations so ?
they provide large windows for large molecules to pass
What are sinusoids ?
capillaries that have large holes in their walls
blood slows down - maximum exchange
What are veins surrounded with ?
connective tissue that they expand into
What is venous return aided by ?
action of muscular pumps - these pumps act around veins exclusively - the arteries are independent of the veins
What are anastomoses ?
Several branches of arteries that join and communicate - allowing uninterrupted flow of blood to tissues they supply
What are arteriovenous anastomoses ?
communications between the veins and arteries
shunt large volumes of blood through a tissue whilst bypassing the tissue bed
What do anastomoses provide ?
alternative channels when one is blocked
What is alternative flow called ?
collateral circulation
What happens if arteries dont anastomose ?
no collateral circulation
supplied areas can die
eg the central artery of the retina
Why is there a net outlflow of fluid at the capillaries ?
blood passes through the capillaries at a high hydrostatic pressure
plasma proteins create a constant oncotic pressure
water is forced back into the capillaries
hydrostatic > oncotic - net outflow
What is the contents of lymph ?
B and T lymphocytes that are produced in the bone marrow
travel in blood circulation to lymphoid tissues
What are lumph capillaries ?
they are blind ended vessles that follow alongisde capillaries
What are lymph nodes ?
flattened enlarge filters - filter foreign material out of the lymph
What do lymph capillaries and nodes drain into ?
larger trunks
What does the thoracic duct drain ?
lower limbs
abdomen
chest wall
What does the bronchomediastinal trunk drain ?
the viscera of the thorax
What do the subclavian trunks drain ?
upper limbs
What do the jugular trunks drain ?
the head and the neck
What are the mechanisms of lymph flow ?
passage is aided from the positive pressure of the abdominal cavity to the negative pressue of the thoracic cavity
smooth muscle in the walls that contract
valves
neighbouring skeletal muscle massages the lymoh vessels
What are the fucntions of the lymphatic system ?
allow lymoh fluid to reenter the venous system
manufacture of antobodies
antigens can be taken to lymph nodes
What are the sites of lymphoid tissue
mucosal associated lymphoid tissue tonsillar tissue spleen thymus gland lymphoid tissue of the gut small follicles are found within these structures
What is the clinical importance of the lymphatic system ?
patterns of lymphatic drainage - usually the patterns of infection spread as antigens travel down these routes
Primary cancer can metastasise down these lyphatic routes - eg breast cancer can metastasise to the axillary nodes
What is a consequence of disrupting lymphatic drainage ?
lymphodema
What are the functions of the nervous system ?
receive sensory info from outside/inside the body
Initiate and regulate behaviour in response to these stimuli
Homeostasis
What is the CNS ?
brain and the spinal cord in the vertebral canal
What are the components of the CNS ?
motor component
sensory component
Association component
What is the PNS ?
31 spinal nerves
12 cranial nerves
Ganglions
What are ganglions ?
collections of neuronal cell bodies outside the CNS
What is the function of the PNS ?
connects peripheral organs to the CNS
What is grey matter and where is it found ?
lacks myelin
collections of cell bodies , dendrites , glia and synapses
central part of the spinal cord
What is white matter ?
bundles of myelinated axons and glia within the CNS
connects areas of grey matter
What are afferent axons ?
carry impulses to the CNS - in the PNS they are sensory
What are efferent axons ?
Carry impulses away from the CNS to muscle and glands
In the PNS they are motor
What is the somatic nervous system ?
controls the bodys voluntary processes (skeletal muscle , bones and joints)
What is the autonomic nervous system ?
controls the bodys involuntary processes - smooth and cardiac muscle (glands and viscera)
What is the structure of a spinal nerve
Central H shaped mass of grey matter - cell body accumulations
Surrounded by white matter of myelinated axons
How do sensory process enter the CNS ?
as dorsal roots
How do sensory process leave the CNS ?
ventral roots
What is the swelling on the dorsal root
dorsal root ganglion
swelling of cell bodies
sensory neuronal cell bodies grouped together
What do the dorsal root and ventral root unite to form ?
mixed spinal nerve
What does the mixed spinal nerve divide into ?
the anterior primary ramus
the posterior primary ramus
Where is grey matter found ?
in the central part of the spinal chord
What is the function of white matter ?
to connect areas of grey matter
What are the 12 cranial nerves ?
olfactory optic oculomotor trochlear trigeminal abducens facial vestibulocochlear Glossopharyngeal spinal accessory hypoglossal
How many cervical vertebrae are there ?
7
How many thoracic vertebrae are there ?
12
How many lumbar vertebrae are there ?
5
How many sacral vertebrae are there ?
5
How many coccygeal vertebrae are there ?
4
How is each spinal nerve lettered and numbered ?
according to the vertebra above
How are the cervical nerves lettered and numbered ?
according to the vertebra below
Are spinal nerves mixed ?
yes- they contain sensory and motor processes
What is the ANS concerned with ?
control and maintenance of the internal environment
What does the ANS consist of ?
efferent pathways to muscles and glands
How are organs innervated by the ANS ?
dual innervation - organs are both innervated by the PNS/SNS
How is the parasympathetic nervous system connected to the CNS ?
via craniosacral outflow - cranial and sacral spinal nerves
How is the sympathetic nervous system connected to the CNS ?
thoracolumbar outflow
T1- L1/L2
How many efferent axons does it take to carry information from the CNS to the target via the ANS ?
2 efferent axons
these synapse at an intermediate autonomic ganlion
What is the relationship between preganglionic and postganglionic axons in the parasympathetic nervous system ?
the preganglionic axons are long
the postganglionic axons are short
the ganglia are in the wall of the target
What is the relationship between the preganglionic and postganglionic axons in the the sympathetic nervous system ?
the preganglionic axons are short
the postgangliomic axons are long
the ganglia are in the sympathetic chain
What is the function of the parasympathetic nervous system ?
rest and digest increases gut motility decreases heart rate increase saliva dilate the cutaneous vessels
What are the parasympathetic ganglia ?
ciliary otic pterygopalatine sub mandibular intra mural
What are the sumpathetic ganglia ?
sympathetic chain
superior cervical - head and neck supply
coeliac
superior mesenteric
What does the skull consist of ?
cranium and the mandible
What can the cranium be split into ?
neurocranium = braincase viscerocranium = facial skeleton
What can the facial skeleton (viscerocranium) be split into ?
the facial skeleton
mandible
What does the coronal suture separate ?
the frontal and the parietal bones
What does the sagittal suture separate ?
separates the parietal bones
What is bregma ?
the point where the sagittal and coronal sutures meet
What is the mastoid process an extension of ?
temporal bone
What does the lamboidal suture separate ?
the occipital and parietla bones
What is lambda ?
the point where the sagittal and lamboidal sutures meet
What is the superior nuchal line ?
it radiates laterally from the external occipital protuberance
What is pterion ?
the H shaped junction between the frontal bone
squamous of the temporal bone
greater wing of sphenoid
Parietal bone
in which bone is the external auditory meatus ?
the temporal bone
Where does the mental foramen open ?
near the second mandibular pre-molar
Where is the hypoglossal canal ?
underneath the occipital condyles
