CHAPTER 41: ANIMAL NUTRITION Flashcards
How can animals extract the nutrients they need from food while not digesting their own tissues?
The compartmentalized processing protects body tissues while allowing enzymes and acids to break down nutrients
What three needs must an adequate diet satisfy?
- chemical energy for cellular processes
- organic building blocks for macromolecules
- essential nutrients
What are the 4 classes of essential nutrients?
- essential amino acids
- essential fatty acids
- vitamins
- minerals
What 4 things do food processing involve?
- ingestion/feeding mechanisms
- digestion
- absorption
- elimination
What are the four main feeding mechanisms of most animals?
- Filter feeders: sift small food particles from water
- Substrate feeders: live in or on their food
- Fluid feeders: suck nutrient-rich fluid from a living host
- Bulk feeders: eat large pieces of food
What are the two processes of digestion
- Mechanical digestion: chewing or grinding
- Chemical digestion: enzymes breakdown food into small molecules that can pass through membranes
Animals with simple body plans have a digestive compartment ______(single opening) that functions in both digestion and distribution of nutrients throughout the body. E.g hydra
gastrovascular cavity
More complex body plan animals have a digestive tube with two openings which are a _______
mouth and anus
Organs specialized for sequential stages of food processing form the _________
mammalian digestive system
In mammals, a number of _______ secrete digestive juices through ducts into the alimentary canal
accessory glands
What are some mammalian accessory glands?
- Salivary glands
- Pancreas
- Liver
- Gallbladder
Food Processing begins in the __________
oral cavity
Saliva contains _______ and _________
mucus and amylase
The tongue movements shape food into a ________ and helps with swallowing
bolus
The throat is also known as the ______
pharynx
The throat is the junction that opens to both the esophagus and the ______
trachea
The trachea leads to the __________
lungs
The esophagus connects to the ______
stomach
Swallowing causes the _______ to block entry to the trachea
epiglottis
What are the two major roles of the stomach
- storage of food
- processes food into a liquid suspension
What is chyme
-The mixture of ingested food and gastric juice.
What prevents chyme from entering the esophagus and regulates its entry into the small intestine
Sphincters
What is the longest compartment of the alimentary canal
small intestine
Most enzymatic hydrolysis of macromolecules from food occurs in the ________
small intestine
Gastric juice has a low pH of ______ which denatures _________
2; proteins
What is gastric juice made out of?
Pepsin and HCL
Is pepsin a protease?
Yes
What are parietal cells?
They secrete hydrogen and chloride ions into the lumen of the stomach
What are chief cells?
They secrete inactive pepsinogen which is activated to pepsin when mixed with HCL.
What does mucus do?
It protects the stomach lining from gastric juice
What adds a new epithelial layer every three days?
Cell division
What is the first portion of the small intestine?
duodenum
What does the pancreas produce?
- Bicarbonate which neutralizes the acidic chyme
- Proteases, trypsin and chymotrypsin
Fat digestion is facilitated by _______
bile salt
The small intestine has a huge _________ that is exposed to the intestinal lumen and greatly increases the rate of nutrient absorption
microvilli surface
What carries nutrient-rich blood from the capillaries of the villi to the liver
hepatic portal vein
What does the liver do?
- Regulates nutrient distribution
- Interconverts many organic molecules
- Detoxifies many organic molecules
Epithelial cells absorb fatty acids and monoglycerides and recombine them into _________
triglycerides
These fats are coated with __________, ________ and __________ to form __________
phospholipids, cholesterol and proteins; water-soluble chylomicrons
Chylomicrons are transported into a lacteal, a lymphatic vessel in each vessel. True/False
True
The large intestine includes what?
colon, cecum and rectum
Colon leads to the ______ and ________
rectum and anus
What is the cecum?
Where the small and large intestines meet
In animals, it aids in fermenting ingested plant material
The human cecum has an extension called the ___________ which acts as a reservoir for symbiotic microorganisms
appendix
The colon completes the recovery of _________ that began in the small intestine
water
________ vertebrates have less specialized teeth
Nonmammalian
________ have large expandable stomachs
Carnivores
Why do herbivores have longer alimentary canals than carnivores?
They need longer time to digest vegetation
What is the microbiome?
The collection of the microorganisms living on the body
What does H.pylori cause?
stomach ulcers
Fermentation occurs in esophageal derivations?
- Rumen
- Reticulum
- Omasum
Herbivorous diet have evolved in the animals’ called ________
ruminants(4 chambers)
What is Aabomasum?
True stomach
What are giant tubeworms?
They have no digestive system and obtain nutrients from mutualistic bacteria within their bodies
The steps in the digestive system are regulated by the _________
enteric nervous system
In humans, energy is stored first in the _______ and __________ in the form of ___________
liver and muscle cells; glycogen
Excess energy is stored in fat in _________
adipose cells
When fewer calories are taken in, the human body expends ________ first then ________________
liver glycogen; muscle glycogen and fat
Glucose homeostasis relies on the opposing effects of two hormones, which are?
insulin and glucagon
What is insulin and glucagon?
- They are both produced by islets of the pancreas
- Alpha cells make glucagon
- Beta cells make insulin
What is the site for glucose homeostasis?
liver
_________ are an exception; they can take up glucose whether insulin is present
Brain cells
What is diabetes mellitus caused by?
It is caused by deficiency of insulin or a decreased response to insulin in target tissues
What is type 1 diabetes?
It is an autoimmune disorder where the immune system destroys the beta cells of the pancreas, sos insulin is not produced.
APPEARS DURING CHILDHOOD
What is type 2 diabetes?
Insulin is produced but the target cell is not responding
GENERALLY APPEARS AFTER THE AGE OF 40
NO EXRERCISE
How do hormones regulate long-term and short-term appetite?
They do by affecting a “satiety center” in the brain
What are some diseases that obesity contribute to?
colon cancer breast cancer type 2 diabetes heart attacks strokes
What is Ghrelin?
It is a hormone that is secreted by the stomach wall and it triggers feelings of hunger before meals
What is insulin?
It suppresses appetite acting on the brain
What is leptin?
It is produced by adipose tissue and suppresses appetite and regulates body fat levels
What is PYY?
It is secreted by the small intestine after meals to suppress appetite
