Homeostasis, Nutrition, Digestion Flashcards
What happens 1st when you stop eating?
- Breakdown glycogen
- about 6 hours after feeding – after turn to fatty acids
Phase 2 after not eating
- Ketosis, fat-burning
- Ketone bodies replace energy fuel
- Athletes may be in it more often
- Brain cannot directly use these, too thick to fit through the BBB
- Brain drains last of glucose
- Recalibrates requirement starts eating ketone bodies
Phase 3 - not eating
Protein burning, rapid muscle depletion
- The body starts eating itself – catabolises
- Mostly, cardiac arrest kills you – tissue degradation
A loss of more than ____% of water can be deadly
12%
How is the shape of enzymes determined?
Hydrogen bonding
Role of Kidneys
Filter blood
remove waste and excess solutes
Urea
Byproduct of protein metabolism
Ammonia
Toxic
How do kidneys work?
- Enter through renal artery
- Branch to specialized capillaries (glomerulus)
- Arterial pressure forces water/solutes out of capillaries
- Into tubule/collecting duct
Nutrients processed by kidney
Glucose, sodium, chloride
Wastes process by kidneys
Urea, creatinine
How do we regulate heat?
a) Conduction
b) Radiation
c) Evaporation
Example: Conduction
Lizard pressed against warm rock
Example: Radiation
Light coloured butterfly gains less heat then dark one
Example: Evaporation
sweating, panting
Endotherms
Maintain a high body temp in cold environments
Ectotherms
depend on environmental heat to maintain their body temperature
Osmosis
Water moving down conc. gradient
High to low
Passive
Why do we require iodine?
To make hormones
Why do we require carbs?
Energy, carbon
Why do we require lipids?
Concentrated energy
Required to make certain compounds
e.g. linoleic acid required to make prostaglandins and cell membranes
Why do we need proteins?
Source of amino acids
We cannot synthesize some amino acids naturally
Peristalsis
Muscle driven movement of the gut
Small Intestine
Epithelial cells absorb nutrients (active transport) and secrete enzymes
Pancreas
Source of digestive enzymes
lipase, proteases, amylase
Liver
Produces bile
bile emulsifies fat and increases efficiency of lipases
What stores bile?
Gallbladder
Amylase
Digests carbohydrates
Proteases
Digests proteins
Lipases
Digests fats
Large intestine
Water is absorbed
some nutrient absorbtion
Lots of normal flora
Gastrin
Causes stomach to produce acid
Secretin
Causes pancreas to send out digestive juice, stimulate stomach to produce pepsin (digests protein) and stimulates liver to produce bile
Chrelin
Produce din stomach and upper intestine when food is absent
stim appetite
Peptide YY
Produced in GI when food is present
inhibit appetite
Lactase
Breaks down lactose
Lactosis
Lack of lactase
digestive problems with milk
Cellulose
Composed of glucose
can’t digest cellulose, animals lack cellulase
Extracellular Matrix
Coating of nonliving material, released by cells of multicellular organisms, often help hold those cells together
Fluid Connective tissue
Cells suspended in liquid matrix
blood and lymph
Fluid portion = plasma
Loose connective tissue
Soft matrix, loosely arranged protein
Hold organs in place + padding
Adipose
Supporting connective tissue
Semirigid/rigid matrix creating strong structures such as cartilage and bone
