Comparative physiology Flashcards
Disadvantages relating to cellulose digestion in ruminants
- Absence of endogenous enzymes capable of digestion of cellulose
- Prolonged time for digestion
- Relatively poor caloric yield
- Large amount of storage space required for voluminous stomachs or colons or both
- Very fine maceration requires prolonged rumination or prolonged caecal fermentation
- Very large amounts of fluid required to liquidise the vegetable mulch, 1/3 body weight saliva per day resulting in particular problems with water conservation
- Large amounts of methane produced which represents a net loss and reduced efficiency, the end products of fermentation are short chain fatty acids
Discuss the features of type 1 muscle fibres
- Type I muscle fibres (slow twitch) – designed for endurance
o High capillary density
o High myoglobin content
o High mitochondrial density and capacity for aerobic respiration
o Higher triglyceride and glycogen content (oxidative phosphorylation and beta oxidation)
Advantages of coprophagy
o Conserving nitrogen
o Maintaining foregut fermentation
o Bacterial synthesis of vitamins and essential amino acids which would not be obtained from diet, e.g. B vitamins
Describe how marine fish maintain their hyposmolality in saltwater
They drink substantial amounts of seawater and the ingested salts are absorbed in the intestines and eliminated via the gills by active transport
Magnesium and sulphate are eliminated in the urine
Describe how freshwater fish maintain hyperosmolality in freshwater
The freshwater fish suffers a steady osmotic influx of water
the excess water is eliminated through urine
Loss of solutes through gills in urine is compensated for by active uptake in the gills
Discuss metabolic adaptations in deep diving mammals
- Higher capacity for anaerobic respiration
- Inc. buffering capacity to cope with higher levels of lactate
- More LDH in liver
- More fatty acid oxidation
