Homeostasis Flashcards
Homeostasis
the maintenance of a constant internal enviornment
Endothermic
energy to regulate its body temperature is produced internally.
Ectothermic
uses external environmental factors to regulate its body temperature.
Advantages of endothermic to ectothermic
Being endothermic allows us to live in cooler areas and regulate our body temperatures to fight off infection. The downside, though, is that regulating body temperature is energetically costly, and warm-blooded animals need more food than cold-blooded ones.
What is the skin made of?
Skin is made from two layers, top layer is epidermis and bottom layer is dermis. All cells at the base of epidermis is dividing by mitosis. The top layer is made up of keratin, which is filled with dead cells
Mitosis
nuclear division giving rise to genetically identical cells.
Skin on homeostasis
The cornified layer is waterproof and hard so it protects the soft layer underneath it, which is always being worn away and is replaced by cells from beneath. Some cells contain melanin.
Melanin
is a dark brown pigment called melanin, which absorbs harmful ultraviolet rays in sunlight, which would damage living cells in the deeper layer of the skins.
The dermis
The inner layer of the two main layers of the skin. The dermis has connective tissue, blood vessels, oil and sweat glands, nerves, hair follicles, and other structures.§
Function of sweat glands
Sweat glands occur all over the body, but are most numerous on the forehead, the armpits, the palms and the soles of the feet. Sweat is mainly water, but it also contains some salts. Its main function is to control body temperature. As the water in the sweat evaporates, the surface of the skin cools.
The hypothalamus
When your hypothalamus senses that you’re too hot, it sends signals to your sweat glands to make you sweat and cool you off.
Muscles work (Temperature falls)
Muscles in some parts contract and relax very fast, which is called shivering. It produces heat.
Metabolism (Temperature falls)
It increases, and processes such as respiration increases as well to release more heat
Hair stands up (Temperature falls)
erector muscle on skin contract, pulling hair up on their end. (helps most animals with fur), this prevents skin from losing heat (insulator)
Blood system (Temperature falls)
it conserves heat, Vasoconstriction occurs
Vasoconstriction
When blood vessels constrict, blood flow is slowed or blocked.
Hair lies flat (Temperature rises)
erector muscles relax, so hair lie down
Blood system (Temperature rises)
Vasodilation occurs
Vasodilation
widening of blood vessels as a result of the relaxation of the blood vessel’s muscular walls.
Sweat (Temperature rises)
Sweat glands secrete sweat, the sweat evaporates from skin surface, along with the heat, thus cooling the body
Negative feedback
negative feedback loops are characterized by their ability to either increase or decrease a stimulus, this is done by hypothalamus, when it detects the stimulas, it sending nerve impulses to your skin to reduce the heat loss from the body
Control of blood glucose concentration
The blood glucose concentration is monitored by islets of Langerhans in the pancreas. After a meal rich in carbohydrates, glucose level in blood increases, which is detected by the pancreas, which then sends insulin through the bloodstreams to all around the body to trigger body cells to take up glucose from the blood and liver to store glucose as glycogen.
Type 1 diabetes
Type one diabetes is caused when the pancreas is not able to produce the hormone insulin
Hyperglycaemia
when blood sugar (glucose) level goes up and stays up
Hypoglycaemia
When level of sugar (glucose) in your blood drops too low
