“The white elements in the picture are the axons from the olfactory sensory cells located at the front of the brain. They carry information about different molecular components of odors. The red parts are the synaptic terminals that are located inside of these axons and these terminals are the cellular sites at which neural information (i.e., action potentials or electric signals) are converted into a chemical signal which then moves over to another neuron and activates it.”
Department of Physiology & Biophysics
- Oliver Braubach
A comparative anatomy of the hand from The Natural History of the Ordinary Cetacea, or Whales (1837), by Robert Hamilton. Diagrams C and D show the bony structures in the flippers of a dugong and a bowhead whale, respectively. Diagram E shows a human arm for comparison.
That awkward moment when your eyes can’t decide if it wants to use cones or rods.
The retina in your eyes contains two types of photoreceptors:
1. Package their secretion in secretory vesicles. The vesicles travel to the surface of the glandular cell and release secretion by exocytosis.
2. Examples: Tears, salivary and gastric juices
1. Form cells that accumulate a product and then the entire cell disintegrates.
2. Example: Sebaceous gland (secretes oil/sebum)
1. Accumulate their secretory products within the apical portions of their cytoplasm. Apical portion then decapitates and pinches off into the lumen of the glands to be transported to the skin surface.
2. Examples: Mammary glands and some sweat glands in the axillary and pubic regions.
1. Found on palms of hand and soles of feet.
2. All five strata are found here (basale, spinosum, granulosum, lucidum, and corneum).
3. Contains sweat glands but no hair follicles or sebaceous glands
1. Covers most of the body
2. Lacks stratum lucidum
3. Contains hair follicles, sebaceous glands, and sweat glands