chapter 5 Flashcards
sperm
only contribution to DNA from males
zygote
start of embryology, first cell then starts to divide after that
morula
soap bubble stage, solid mass of blastomeres (early embryonic cells)
blastula
hollow sphere, consists of hundreds of thousands of blastomeres, depending on the species
-blastocyst is name for blastula in mammals
-inner cell mass is the body of the embryo and embryonic membranes around the embryo
-each cell (blastomere) contains some of the original cytoplasmic contents of the zygote (cytosol and organelles including mitochondria
-outer layer of the blastula is called trophoblast and will form the placenta in placental mammals
gastrula
forms after the blastula during gastrulation
-major rearrangement of cells
-most cells arrived at final destination
-gut formation, early gut forms
-three germ cell layers; embryonic tissue layers are endoderm, mesoderm, ectoderm
endoderm
gut, liver, pancreas, bladder, pharynx, lungs
ectoderm
skin epidermis, brain and spinal cord
mesoderm
skin dermis, muscle, bones, kidneys, gonads, heart, blood vessels
neuralation
formation of the neural tube
-nerve formation, neural plate changing
-cells move down neural folds called neural crest cells
species differences during embryology
amount and distribution of yolk in egg
gastroceol or archenteron
the true coelom (body cavity) inside the gut
neural plate
give rise to the central nervous system (dorsal tubular nerve cord)
neural folds
cells move down from neural crest cells
neural tube
during neurulation, nerve formation, neural plate changing
epimere
will form somite, this gives rise to lots of things
mesomere
will form kidney
hypomere
will form coelom, peritoneum, mesenteries… bones of appendages, heart, circulatory system, gonads, connective tissues, smooth muscle, cardiac muscle
somite
all mesoderm, three populations of cells in each somite which are segmentally arranged blocks of tissue in the embryo from the neck to the tail
dermatome
dermal layer of skin and smooth muscles in the dermal layer of skin
myotome
segmental muscles of the body (appendicular and axial muscles)
scleratome
vertebrae
mesentery
define the coelom, hold organs in place, lubricate organs to reduce friction
neural crest cells
ectodermal cells that enter embryo as neural tube forms
-migrate to many parts of body and become
-spinal/cranial ganglia, Schwann cells, adrenal medulla, skin pigment cells, lower jaw bone and cartilage
placodes
ectodermal cells that form thick patches over parts of head/anterior body (sensory nerves/epithelium)
-sensory nerves in head
-sensory receptors (otic, olfactory, lateral line, lens of eye)
differentiation of epithelia
simple (one cell thick) or stratified
-squamous (flat cells) or cuboidal or columnar
-membranes (epithelia alone, type 1) or glands (mostly exocytotic cells, type 2)
basement membrane
underneath epithelia, part of extracellular matrix
lumen
specific portion of the epithelia, block of cell layer
exocytosis
secreting something
endocytosis
bringing something in
exocrine gland
ducts that carry away product
endocrine gland
product (hormones) released directly into circulatory system where it’s carried away
connective tissue
cell type + extracellular matrix
-matrix has ground substance (hard, soft, liquid) and a fiber (usually collagen)
mesenchyme
embryonic only and source of all other connective tissue
-loose collection of cells
adipose
no matrix, only fat cells, fat storage
areolar
holds other tissues together (fibroblasts + collagen + elastin)
-least specialized type of connective tissue
-fits with general rule of connective tissue
-superficial fascia is example of areolar (holds skin down to muscle)
fibrous
most common general type
-fits general rule: fibroblasts, and matrix with fibers in a gel-like ground substance
hyaline cartilage
glassy appearance
-form model of adult skeleton in embryo before ossification
-found on end of long bones, tips of ribs, tracheal rings, in skull
elastic
see flexible places like ear, tip of nose, epiglottis
fibrocartilage
abundant collagen fibers
-especially in places with a lot of tensile forces such as intervertebral discs in knee, where femur joins pelvis
chondrocytes
cartilage cell type, trapped in a lacunae space
chondroitin sulfate
ground substance for cartilage matrix (gel-like)
avascular connective tissue
no direct blood supply, blood vessels and nerves end at perichondrium and respiratory gases and nutrients get to chondrocytes by simple diffusion
bone
made of cylinders of matrix and cells, called osteons or haversian systems
tree-ring like lamellae
made of layers of bone matrix and cells
osteocytes
maintain old bone
osteoblasts
make new matrix
osteoclasts
degrade matrix
periosteum
outermost sheath of connective tissue
classification of bone
compact (densely packed osteons) or spongy
-endochondral or intramembranous bone (form differently during development
-long or flat
diaphysis
cartilage converted to bone, first along length of shaft
-become hollow (medullary cavity) as blood vessel center
-primary ossification
metaphysis
primary and secondary ossification centers meet here
epiphysis
secondary ossification occurs at ends of bone
long bones
use endochondral growth
-cartilage model, appears from mesenchyme
-diaphysis to epiphysis to metaphysis
membrane bones
use intramembranous growth
-flat layers of mesenchyme secrete bone matrix (no cartilage intermediate)
dermal bones
mesenchyme was part of skin dermis (part of skull and pectoral girdle)
sesamoid bones
bone formed within a tendon (knee-cap/patella and wrist/pisiform bone)
synovial joint
moveable
-joint capsule
-synovial fluid
-hyaline cartilage
-ligaments
synarthrosis joint
immovable
-known as sutures or symphyses
joint
where two separate elements of bone or cartilage meet
-inside walls lined with fibrocartilage, fibrous connective tissue, enclosing the joint cavity, that secretes lubricating fluid= synovial fluid
joint capsule
synovial capsule
synovial joint
diarthrosis joint
hyaline cartilage
cape the ends of long bones
ligaments
fibrous connective tissue that joins bones together at joints
synarthrosis joint
no joint capsule, no lubricating fluid, no capsule membrane
sutures
connected by fibrous connective tissue (skull)
symphyses
connection of cartilage (pelvis)
