Lecture: Viscera and Visceral Systems Flashcards
What are the types of viscera?
Hollow and solid
What are the layers of hollow viscera?
Lumen > mucosa > muscularis > serosa
What are the functions of each layer of hollow viscera?
Lumen: is the actual hole
Mucosa: increases surface area for absorption
Muscularis: Muscle for contraction; peristalsis
Serosa: reduce friction with other organs
What are sphincters and where are they located?
Located in hollow viscera. They limit the amount of flow through the viscera. i.e. urine etc
What are the types of sphincters? Describe them
Anatomical and functional.
Anatomical can be voluntary or involuntary and they have muscles.
Functional does not have muscle thickening, it relies on surround structures to “close off” the sphincter
Give an example of an anatomical sphincter.
GIT is involuntary but the anus is voluntary; 2 lines of defence
Give an example of a functional sphincter
Kidney filters to make urine; that travels through the ureter to the bladder. The contraction of the bladder prevents urine from re-entering the ureter (backflow).
What are solid viscera?
usually glands, produces hormones etc.
What are the two types of glands?
exocrine and endocrine
What is the difference between exocrine and endocrine?
endocrine glands deposit hormones straight into the blood stream whereas exocrine produces it elsewhere and enters the blood stream via a duct
What is special about the pancreas?
it can be both an endo and exocrine gland. It can produce digestive enzymes into the small intestine, or it can secrete hormones which circulate in the blood
Describe how serous membranes are formed
Starts off with a body wall behind a cavity and a viscera. The cavity enlarges so the viscera starts to move into the cavity. Eventually, the cavity surrounds the viscera along with its body wall. The viscera is enveloped. End up with a double layered membrane; parietal and visceral
What is THE mesentary?
Where the serosa joins up, but there is still a little hole to allow for vessels and nerves to innervate the viscera
What is paired and unpaired viscera?
Paired has neurovascular supply from their own side of the body, unpaired has from both. Unpaired develops in the midline then moves to one side i.e. the heart.
