EXAM 3 REVIEW Flashcards
Where does fertilization occur in humans?
-In the upper third of the oviduct
Which stages is produced by the cleavage alone?
- Morula
- Blastula
How many germ layers are produced in embryos?
3
What is the name of the location of where the germ layers are produced?
-Gastrula
What is the characteristic of sea urchin eggs in terms of their polarity?
-Animal/ vegetal poles are determined by position of the nucleus so when a sea-urhcin egg is cut vertically in half they’ll develop normally
What did the experiments of the Xenopus eggs w/ antibiotic actinomycin D demonstrate?
-That early development requires maternal mRNA
What are Morphogens?
-They are signalling molecules that establish the Anterior-Posterior axis in development
What is the process of development?
- Cell division
- Differentitation
- Pattern Formation
- Morphogenesis
What is an important characteristic of Morphogens?
-They diffuse from their source to produce a concentration gradient
What is the purpose of Apoptosis during development?
-It sculpts the body structures
What are the Homeobox-containing (HOX) genes?
-They code for products that establish the segment fate in an embryo
What is an important characteristic of Hox genes?
-They contain a highly conserved DNA sequence
How is the human lens formed during development?
-It’s formed via induction during development
What are important characteristics of stem cells?
- They are found in your body
- They respond to Molecular differentiation cells
What occurs to the ligand when a pre-synaptic neuron releases an inhibitory transmitter?
-It’ll bind to receptors on the dendrites of the post-synaptic neuron and cause the cell to hyperpolarize
What occurs when skeletal muscles are at rest?
ADP and Pi are bounded to the myosin heads
What is a characteristic of Type I muscle fibers?
-They contain high capacity for Aerobic respiration
What role do T-Tubules play?
-They propogate action potential through a myofiber
Where is Myoglobin most abundant?
-It is more abundant in your smaller diameter muscle fibers
What happens if ATP is not available to skeletal muscle?
- The rigor mortis could occur
- The cross bridges couldn’t be broken
What is required for skeletal muscle to produce it’s sliding filament action?
- ATP hydrolysis at the myosin heads
- Calcium binding to troponin
What causes your muscle to bulge when you flex your arm?
-The sarcomere thickens bc actin myofilaments slide past myosin myofilaments
How is skeletal muscle organized?
-It’ organized into smooth sarcomeres
How does cardiac muscle look like?
-It has intercalated disks
What causes the degeneration of neurons in ALS?
-When toxins are secreted by neuronal support cells
What results in the muscle degeneration in ALS?
-When the motor neurons degenerate
Why are my skeletal muscles multinucleated?
-Bc of the multiple myoblasts that were fused together during embyronic development
What is Acetylcholine?
-A neurotransmitter
How is Acetylcholine broken down?
-By enzymes that were secreted by the post-synaptic cell
