Digestion and excretory system (not finished) Flashcards
What are the four levels of organization in the body?
Cells, tissues, organs, and organ systems
What are tissues?
A group of cells that perform a single function
What are the four types of tissues?
Epithelial tissue, connective tissue, nervous tissue, and muscle tissue
What is epithelial tissue?
The issue that lines the interior and exterior of body surfaces (ex: skin, stomach)
What is connective tissue?
A type of tissue that provides support for the body and connects its parts. This includes fat cells, bone cells, and blood cells.
What is nervous tissue?
Nerve impulses are transmitted throughout the body by the tissue. Neurons the cells that carry these impulses.
What is muscle tissue?
Movements of the body are possible because of this tissue.
What is an organ?
A group of different types of tissues that work together to perform a single function
What is an organ system?
A group of organs that perform closely related functions. Interact to maintain homeostasis
What is homeostasis?
The relatively constant internal physical and chemical conditions that organisms maintain despite changes in internal and external environments
What is feedback inhibition?
The process in which a stimulus produces a response that opposes the original stimulus
What is another name for feedback inhibition?
negative feedback
List the digestive system parts in order
Mouth, esophagus, stomach, small intestine, large intestine, rectum then anus. (+liver and pancreas)
Describe the chemical and mechanical food processing in the mouth.
Chemical: saliva (enzyme amylase) breaks down the food into molecules
Mechanical: Teeth turn the food mushy and stuff (gross)
What is a bolus and when does it form?
A bolus is the result of chewed food; it forms in the mouth after chemical and mechanical digestion
Describes what happens in the esophagus (vocab: epiglottis, trachea, bolus, peristalsis, cardiac sphincter)
As the bolus starts going through the esophagus, the epiglottis loses over the trachea (pathway to lungs) so that you don’t choke. Peristalsis (contractions of smooth muscles) moves bolus down to stomach. The cardiac sphincter stops food from going back up when it gets into the stomach.
Describe what happens in the stomach (vocab: chemical/mechanical digestion, PH/hydrochloric acid, pepsinogen, mucus, chyme, cardiac sphincter)
Chemical digestion: As the bolus goes into the stomach, mucus and hydrochloric acid get released by cells. Mucus protects the stomach lining destroyed, while the hydrochloric acid lowers the PH of the stomach to 1. The combination of HCl and pepsinogen creates pepsin, an enzyme that breaks down food into peptides.
Mechanical digestion: the stomach muscles move around and thus digest the food. They do this by alternating muscle contractions. The end result of this is a substance called chyme. As chyme moves to small intestine, cardiac sphincter (another one) prevents low PH from coming into the small intestine or the chyme from going back up.
What substance lowers the PH in the stomach?
Hydrochloric acid
What substance protects the stomach from hydrochloric acid?
mucus
What can occur if someone’s cardiac sphincter doesn’t work properly (food goes back up)?
acid reflex/heart burn
Where does the act of digestion actually take place?
in the small intestine