DSF wk 1 obj Flashcards
Define components of the skeletal system, including major supportive structures
206 bones Living CT Vascular and innervated Functions: Support, protection, storage, mechanical basis for movement, blood cell production Cartilage: Avascular
Describe the classification of bones and their features/markings
All bones has superficial thin layer of cortical bone (strength; weight-bearing) around a central mass of spongy bone
Some have medullary (marrow) cavity
Classified according to shape: long, short, flat, irregular, sesamoid (protect tendons from excessive wear, often change angle of tendons as they pass to attachments)
Periosteum: external, fibrous CT, tough and highly vascular, helps anchor muscles to bone, reacts to trauma
Endosteum: internal, ill-defined largely cellular membrane
Describe parts of the axial and appendicular skeleton
Axial: Midline structures of skeleton - bones of head, neck, trunk
Appendicular: Bones of the arms, legs, pelvic and pectoral girdles (all paired)
Describe organization of the NS into anatomic divisions (CNS, PNS) and functional divisions (somatic, autonomic)
CNS: brain and spinal cord
PNS: cranial nerves (12 pairs), spinal nerves (31 pairs), autonomic nerves
Somatic NS: voluntary. Sensory inputs from skin surface, skeletal muscle, bone, tendon, joints. Motor outputs to skeletal muscles
Autonomic NS: Visceral - involuntary. Sensory inputs from viscera and blood vessels (autonomic reflexes, pain signals from viscera). Motor output to cardiac muscle, glands, smooth muscle in walls of organs and vessels.
ANS subdivisions - Sympathetic (fight or flight) and Parasympathetic (rest and digest).
Somatic and Autonomic both contain sensory (afferent) fibers and motor (efferent) fibers
Describe the structure of typical neurons, the different functional types and their targets for innervation
See diagram on slides for structures
Oligodendrocytes: glial cells of CNS
Schwann cells: glial cells of PNS
Describe the gross anatomy of the spinal cord and its anatomic relations to vertebrae
(Except in upper cervical spinal cord) the vertebral body closest to a spinal cord segment is at least 1 level higher, and often many more (ex: lumbar cord: T10-T12 vertebrae)
Discuss how spinal nerves and spinal cord segments are named and numbered
31 pairs of spinal nerves: named for section of spinal cord from which they arise
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
In cervical spinal cord: spinal nerves exit above the corresponding vertebra
Rest of spinal cord: spinal nerves exit below the corresponding vertebrae
Spinal nerves exit vertebral column via intervertebral foramen
Draw and label a cross-section of the spinal cord including dorsal and ventral horns, gray and white matter, dorsal and ventral roots, DRG, spinal nerve, dorsal and ventral rami
Draw out
A spinal cord segment is comprised of a pair of spinal nerves
Nerve rootlets from the spinal cord converge to form 2 roots: Anterior (contains motor fibers whose cell bodies are in spinal cord gray matter - anterior and lateral horns) and Posterior (contains sensory fibers whose cell bodies located in spinal ganglion, DRG, outside of spinal cord)
Anterior and posterior roots unite to form a spinal nerve, which contains both motor and sensory fibers
Spinal nerve immediately divides into Anterior ramus and Posterior ramus
Anterior ramus: innervates muscles of anterior and lateral trunk, upper and lower limbs and overlying skin (stay as separate nerves to innervate trunk - intercostal nerves, form plexus to supply limbs)
Posterior ramus: innervates joints of the vertebral column, deep muscles of the back, and overlying skin (stay as separate nerves)
Draw the pathway and fiber content of a typical intercostal nerve
Sensory receptors - pseudounipolar sensory neuron - DRG - posterior root of spinal nerve
Anterior root of spinal nerve - somatic multipolar motor neuron - effector organ (skeletal muscle)
Anterior root of spinal nerve - presynaptic and postsynaptic autonomic multipolar motor neurons (synapse w/in autonomic ganglion) - synapse on glands/cardiac muscle/smooth (involuntary) muscle of organs
Define the concept of a dermatome and its relationship w/ a spinal cord segment (segmental innervation)
Each spinal cord segment has somatic and autonomic components
Dermatome: map of segmental sensory innervation
Each spinal cord segment is responsible for cutaneous innervation of a particular region
C1-C8: dorsal head, neck, shoulders, arms, hands
T1-T12: anterior trunk and abd, medial arms
L1-L5: posterior lower back, anterior and lateral legs, soles of feet
S1-S5: genitals, posterior legs
Describe in general terms, the structure of the vertebral column and the components of a typical vertebra
See diagrams on slides
Define the primary and secondary curvatures of the spine and differentiate b/w abnormal curvatures
Primary curvatures: Sacral, Thoracic - form during fetal development
Secondary curvatures: Lumbar, Cervical - develop after birth (from walking and lifting head, respectively)
Kyphosis - can be caused by compression fxs (elderly) - outward rounding of upper back, “hunchback”
Lordosis - excessive inward curve of the spine
Scoliosis - sideways curvature of the spine
Describe the location and function of the intervertebral discs and major supporting ligaments of the spinal column
Intervertebral discs: connect adj vertebrae, shock absorption
Disc reinforced by anterior and posterior longitudinal ligaments
Disc herniation most often occurs in posterolateral region - annulus fibrosus is thinner and has fewer lamellar in posterior aspect
Ligaments connecting adj vertebrae: resist hyperflexion
Define and list examples of extrinsic and intrinsic back muscles
Intrinsic: Deep muscles (Splenius-capitis and cervicus, Erector spinae-Spinalis, Longissimus, Iliocostalis, Transversospinales-Semispinalis capitis, Multifidus, Rotatores)
Extrinsic: Intermediate (Serratus posterior superior and inferior - Respiratory) and Superficial (Trapezius, Latissimus dorsi, Rhomboid major and minor, Levator scapulae - Appendicular)
Describe the location, function, and innervation of the superficial (appendicular), intermediate (respiratory), and deep (intrinsic) back muscles
x
Describe the pattern of arterial supply and venous return within the back
x
Review the gross anatomy of the spinal cord and supporting meningeal structures
Meningeal spaces of the brain and spinal cord are continuous w/ one another
Dura mater, archnoid mater, pia mater
Pia mater: Denticulate ligaments (attach spinal cord to superficial meningeal layers) and Filium terminale (connects spinal cord to coccyx, provides tension to stabilize spinal cord)
Formulate the stages of prenatal development with emphasis on their relative vulnerability to teratogens.
0-2 wks Germinal period: not sensitive usually, high rate of lethality can occur
3-8 wks Embryonic period: period of greatest sensitivity, each organ system will also have a peak sensitivity
9-38 wks Fetal period: decreasing sensitivity, period of functional maturation
Compare and contrast b/w embryonic/fertilization and gestational/menstrual age.
During a regular menstrual cycle, ovulation occurs at day 14. Assuming fertilization to occur ~during same time, embryo is already 2 wks old when the mother misses her next period.
Gestational (menstrual) age [counted from the 1st day of the LMP] is always 2 wks greater than the embryonic (fertilization, counted from day of fertilization) age.
Construct the development of the embryo from a zygote to a blastocyst.
W/in 24 hrs zygote formation, embryo undergoes series mitotic divisions (cleavage) in which the cell #s increase at expense of size (no cytoplasm synthesis) - loosely packed, increasingly smaller cells - blastomeres.
~3 days after fertilization, embryo divides to form a 16-cell morula, that enters uterine cavity.
Morula eventually differentiates into a blastocyst, in which cells organize into an inner (embryoblast) and outer (trophoblast) cell mass.
Embryoblast - embryo
Trophoblast - placenta
Illustrate the stages, duration, and molecular regulation of the preimplantation phase.
Degeneration of zona pellucida
Adplantation - Initial adhesion of blastocyst to uterine epithelium - slows in motility, “rolls” on surface, aligns w/ the inner cell mass closest to the epithelium, and, stops
Initial attachment mediated by L-selectin on trophoblast cells and its carbohydrate receptors on the uterine epithelium
Critique the microstructure of the uterine endometrium and the phase of the menstrual cycle at implantation.
~Days 6/7-13: blastocyst implantation
Occurs in the functional (compact) layer of the endometrium during the secretory phase of the ovarian cycle
Decidua: specialized, highly modified endometrium of pregnancy.
Transformation of endometrial stromal cells, occurring initially at site of implantation: become polyhedral, loaded w/ glycogen and lipids, intercellular spaces filled w/ extravasate.
Decidualization: transformation of secretory endometrium to decidua, dependent on estrogen and progesterone and factors secreted by the implanting blastocyst.
Outline the normal types of implantation and predict the clinical outcomes of extra-uterine pregnancies.
Normal: Implantation hemorrhage - varies in amount/duration/character from regular menstrual bleeding - around days 13-14 (days 27-28 of menstrual cycle)
Cells of syncytiotrophoblasts erode through endothelial lining of maternal capillaries
Ectopic pregnancy: (extra-uterine implantation) most common in the uterine tube. Can be caused by PID. Ruptured tubal pregnancy is surgical emergency - hemorrhage
Mother presents during 1st trimester w/: abd pain, vaginal bleeding, signs of internal hemorrhage/shock (hypotension, tachycardia, rapid and feeble pulse)
Design the development of the bilaminar germ disk, amnion, chorion, amniotic and chorionic cavities, and the yolk sac during the 2nd week of embryonic development.
Day 8: Trophoblast differentiates into cytotrophoblast and syncytiotrophoblast (secrete hCG: maintain decidua and corpus luteum)…Embryoblast differentiates into epiblast and hypoblast
Day 9: At embryonic pole, vacuoles appear in synctium and fuse, forming Trophoblastic lacunae. Flattened cells from hypoblast form thin exocelomic membrane - Heuser’s Membrane - lines exocoelomic cavity, primitive yolk sac. Cavity formed w/in cells of epiblast - Amniotic cavity.
Days 11-12: new cells derived from yolk sac appear b/w cytotrophoblast and Heuser’s membrane - extra-embryonic mesoderm…cavities develop w/in newly formed mesoderm; coalesce to form extra-embryonic coelom - Chorionic cavity.
Design the process of gastrulation w/ emphasis on the morphogenetic role of the primitive streak in forming the trilaminar embryo.
Gastrulation: 3rd wk - process that establishes the 3 definitive germ layers of the embryo (ectoderm, intra-embryonic mesoderm, endoderm), forming a trilaminar embryonic disk
Primitive streak forms day 15, caused by proliferation of epiblast cells.
Predict the consequences of ineffective gastrulation (caudal dysgenesis) and failure of regression of the primitive streak (sacrococcygeal teratoma).
Caudal dysgenesis: occurs if gastrulation stops too soon - head and thoracic regions of embryo are well developed, but insufficient cells available to form normal pelvis, GU organs, and lower limbs. Death usuallu from defective kidney formation. Rare but mostly observed in fetuses of diabetic mothers.
Sacrococcygeal teratoma: Common congenital germ cell tumor, develops from abnormal remnants of primitive streak. Tumor consists of derivatives of all 3 germ layers. Polyhydramnios common b/c increased fetal CO - often preterm labor and premature membrane rupture. Severe cases - Maternal Mirror Syndrome - mother develops HTN, hyperemesis, pulmonary edema, proteinuria.
Critique the formation of the notochord and its role in the differentiation of nerve tissue.
Some mesenchymal cells that have ingressed through the primitive streak migrate cranially from the primitive node and pit, forming a median cellular cord, the notochordal process - which grows cranially b/w the ectoderm and endoderm until it reaches the prechordal plate.
As differentiation continues, the cells of the notochord plate detach from the hypoblast and form a continuous line of cells called the notochord - critical for establishing the midline and axis of embryo - important signaling center for inducing axial skeleton.
Eventually forms the nucleus pulposus of each intervertebral disc.
Discuss the fate of the notochord in adult human being and predict consequences of its incomplete involution (chordoma).
Chordomas: malignant neoplasms from cellular remnants of the notochord . Frequently affects sacrum - rare, slow-growing, primary bone tumor.
Notochord eventually forms the nucleus pulposus of each intervertebral disc.
Formulate the stages of neurlation and the initial steps in the genesis of the CNS and PNS.
Notochord and prechordal plate induce the overlying ectoderm to thicken and form neural plate - initiation of Neurulation.
Occurs in cranial-to-caudal sequence.
Neural folds - elevated lateral edges of neural plate - fuse to form neural tube.
Design the genesis of the neural crest cells and outlines its derivatives.
Neural crest cells originate from edges (crests) of neural folds as neurulation proceeds. Form along entire length of neural tube in neuroectoderm cells.
Migrate away from neural tube to form many different tissues - PNS, Pia and Arachnoid mater, CT, dermis, some bones of head and neck, melanocytes, cardiac septa, medulla of adrenal gland, parafollicular cells of thyroid
Neural crest cells are incredibly sensitive to insults from teratogens.
