Embryology 1 Flashcards
What is the word used to explain pre-natal development?
embryogenesis
What processes does embryogenesis include?
- organogenesis
- proliferation
- specialization
What is organogenesis?
the formation of body structures & organs
What is proliferation?
cell division
What is specialization?
cell differentiation
What does embyogenesis produce?
The great variety of cell types and extracellular products found in the body.
What is the ‘time’ in which ‘embryology’ occurs?
fetus –> giving birth
What is the first cell of the organism? What marks the beginning of the prenatal period?
- female/male sex cell
- oocyte/spermatozoa cell
- union of these two cells marks the beginning of the prenatal period
What is the first stage of embryogenesis?
pre-embryonic stage: period of proliferation of specialization (differentiation) of the zygote.
What is the second stage of embryogenesis?
embryonic period:
- organogenesis
- formation of body structures and organs
- the time from fertilization to the earliest (primordial) stages of organ development
- 30 days- dog, cat, sheep, pig;
60 days- horse, cattle, human.
What is the third and final stage of embryogenesis?
fetus period:
- maturation of tissues and organs
- rapid body growth
- the time between the embryonic period and parturition (the end of gestation)
What is the name of the mature sperm cell?
spermatozoa
Explain the structure of the spermatozoa.
-
flattened head
covered by the acrosomal cap (+ hydrolytic enzymes) - axonemal complex in the sperm tail (+ mitochondria)
- short neck (+ centrioles +origin of the coarse fibers)
- middle piece (+mitochondria)
- principal piece (+fibrous sheath)
- end piece (+axonemal complex)
What does the acrosomal cap include? What is its function?
- hydrolytic enzymes
-
penetration of the
ovum
What is the sperm tail axonemal complex helically wrapped by?
mitochondria
What does the sperm short neck include?
- centrioles
- origin of the coarse fibers
What does the middle piece of spermatozoa include? What is its function?
Mitochondria:
- helically wrapped (around the coarse fibers and the axonemal complex).
- provide the energy for movement of the tail
- responsible for the motility of the sperm.
What does the principal piece of spermatozoa contain?
fibrous sheath:
- external to the
coarse fibers and the axonemal complex.
What does the end piece of spermatozoa contain?
axonemal complex
What are the 4 principal pieces of spermatozoa?
1) head (+acrosome, nucleus, connecting piece)
2) midpiece (+mitochondrial sheath)
3) principal piece
4) end piece
2+3+4=sperm tail
What is the correletion between the neck and midpiece of the spermatozoa?
- neck is a part of the midpiece
- midpiece is the first part of the tail (proximal to the head)
What is the neck of a sperm?
The binding site of the spermatozoa head and tail.
- very short
What are some principal features of the tail?
- densely packed mitochondria
- central pair of microtubules (core)
- outer doublets
- outer dense fibers
- fibrous sheath
What is the function of the cell cytoskeleton?
- prevents cell from collapsing
- maintains cell shape and structure