Homeostasis & Digestion Flashcards
Homeostasis (Definition)
Process of maintaining a relatively stable internal
environment despite changes in external surroundings
- Variables are maintained within a narrow range
- Compensatory mechanisms are brought in if variables deviate too far
Homeostatic control systems have several components :
SP. S. B. E
- Set point : normal value for a variable
- Sensor : the monitor or detector
- Brain : the relay point for information (control center)
- Effector : the responder bringing values back to set point
Negative vs Positive feedback
Negative feedback
- Occurs when changes are counteracted and no more compensation (by effectors) is needed
Positive feedback
- Consits of amplifiying the initiating stimulus
Thermoregulation - Endotherm & Ectotherm
- Endotherm : an animal that can maintain their body temp despite outside environment
- Ectotherm : an animal that can’t control their body temp so it is similar to outside environment
Ways to mitigate Internal Temps (Thermoregulation)
R. Condu. E. Conve.
- Radiation
- Conduction
- Evaporation
- Convection
Ways to increase body heat (Thermoregulation)
Insu.Shiver.Hair.
- Insulation : Heat can be retained through insulation from blubber, fur, feathers etc
- Shivering : the rapid contraction of muscles to
generate heat - Hair : Arrector pili muscles attach to hair follicles and cause thehair to stand up, increasing its insulating effect
Blood Vessels (Thermoregulation)
Dilation & Constriction
Blood vessels in the skin can dilate or constrict
depending on outside temperature
- Constriction : makes vessels smaller, so less blood flows and less heat lost to surface skin
- Dilation : can be used in conjunction with convection to cool overall body temps
Countercurrent Heat Exchange (Thermoregulation)
Vessels run near each other and share warmth
Osmoregulation Process
Blood passes through glomerulus (a capillary bed)
- Nephron acts as a filter, letting waste through to be excreted
- “Fine-tuning” (osmoregulation) gets done in tubules in which it adds/removes water and solutes
Osmoregulation (Definition)
The process by which water and
solute concentrations are maintained at desired
levels
Digestion (Path)
- Esophagus
- Stomach
- The Small Intestine
- Add Ins - Pancreas & Liver
- Large Intestine
Digestion
- Animals obtain nutrients by consuming other organisms
- Mastication (chewing with teeth) breaks food into smaller pieces
- Enzymes (in saliva) chemically break down food too
- Swallowing begins as food is
compacted into a bolus by the tongue
Esophagus
- Bolus
- Peristalsis
The bolus moves to the esophagus (a long tube)
- Peristalsis, a combination of circular and longitudinal smooth muscle contractions, push the bolus to the stomach
The Stomach
- C Sphincter
- Storage & Chyme
- SA & P –> break food
- Pyloric sphincter
A cardiac sphincter regulates
passage of bolus from esophagus
to stomach
- The stomach provides storage of
food and continues digestion
(mechanical and chemical) into
chyme
- Stomach acid and pepsin (an enzyme)
help break food down further - Pyloric sphincter regulates chyme
movement to small intestine
The Small Intestine
- Absorption
- 3 Parts –> D. J. I.
The small intestine completes digestion and
does most of the body’s absorption
- It is separated into the duodenum, jejunum, and
ileum
