A&P Exam 4 Flashcards
5 characteristics of cells
- Irritability (stimulated by environment)
- Growth
- Spontaneous movement
- Metabolism (use food/oxygen to build/repair tissue)
- Reproduction
Cells consist of highly organized masses of __________.
protoplasm
Landmarks of the nucleus
- Endoplasmic reticulum
- Chromatin (DNA & chromosomes)
- Nucleolus & ribosomes
- synthesis of protein
Landmarks of cytoplasm
- Made up of 70-80% water. Incudes:
- Mitochondria
- ATP
- Golgi Apparatus
- Lysosomes
- digestive organ of the cell
- Mitochondria
Intracellular vs. extracellular fluid
- Intracellular: inside the cell
- Extracellular: cells float in this
Mitosis
- Cell division for growth & development
- One cell produces 2 identical, diploid cells
Meiosis
- Cell division for the formation of sperm/eggs
- Produces identical, haploid information
- 1 cell → 4 cells w/ half of the information
Blastocyst & trophoblasts
- Blastocyst: fluid-filled sphere created after successful fertilization (meiosis) and cell division (mitosis).
- forms embryonic tissue
- Trophoblasts: outer layer of cells surrounding inner mass
- attaches to uterine wall & becomes placenta
Endoderm
Inner cell mass of blastocyst begins to differentiate & proliferate to form endoderm early in development.
- layers become yolk sack & amniotic cavity
Yolk sack
Formed from one layer of endodermal cells early in development.
Amniotic cavity
Fluid-filled cavity that develops from inner cell mass cells of endoderm early in development.
Embryonic Disc
Inner cell mass including yolk sac and amniotic cavity early in development.
Primitive streak
Formed from ectodermal cells at the caudal end of the embryonic disc early in development.
Henson’s Node
Formed from layer of mesodermal cells that grow laterally from the primitive streak early in development.
Notochord
Primitive axial skeleton that grows from Henson’s node along the midline axis of the embryo early in development.
Prochordal plate
Found at rostral end of embryonic disc early in development.
Procardiac area
Found at rostral end of embryonic disc early in development.
Neural plate
Thickening of the ectoderm over the neural plate early in development. Lateral margins grow upward to form neural tube, which will develop into the entire CNS.
Flexion
Occurs during week 3. Intraembryonic structures grow rapidly and cannot maintain platelike position, so embryo is thrown in a series of folds.
Cephalic fold
Formed from rapid growth at cephalic end (toward the head) during week 3.
- Prochordal plate (now called buccopharyngeal membrane) folded under embryonic head
- Procardiac area also carried under developing head
3 primary layers of tissue during the flexion stage
- Ectoderm: outermost tissue. Forms epidermis of skin, teeth, nervous system, hair, nails & epithelial tissue
- Mesoderm: forms most of connective tissue
- Endoderm: forms lining of digestive and respiratory tract
Prosencephalon
Forebrain
Stomedium
Primitive mouth. Deepens at week 4 to communicate with foregut.
Branchial arches (general)
- Lateral walls of anterior part of foregut differentiate into bilateral branchial grooves
- As these depressions grow, they meet at the midline and form branchial arches (bumps)
- 4 of the 6 are visible externally:
- mandibular
- hyoid
- third
- fourth
- fifth
Branchial arch 1
Mandibular arch. Forms lower lip, muscles of mastication, mandible, anterior tongue, and some middle ear structures.