living control mechanisms Flashcards
1
Q
homeostasis
A
maintenance of a constant internal environment e.g. temp, potassium, hydrogen ion, blood oxygen, glucose
Cells must communicate with each other to achieve homeostasis – there needs to be a co-ordinated response
2
Q
autocrine
A
cell releases signal, the same cell then acts as a receptor to that signal
3
Q
paracrine
A
(cell produces signal, different cell that is a short distance away acts as a receptor , signals diffuse across gap)
e.g. interleukins - signalling to immune system mainly between white blood cells
4
Q
endocrine
A
(signal travels in blood stream to a more distant target)
organs/glands include: hypothalamus, thyroid, pancreas, ovaries
5
Q
hormone
A
molecule that act as a chemical messenger Classified according to structure • Amino-acid derivatives • Peptide • Steroid
6
Q
amino acid hormones
A
- Synthesised from tyrosine
- E.g. adrenaline
- Produce quick reaction in the body
7
Q
peptide hormones
A
- Made of amino acids
- Vary in size from few amino acids to small proteins
- Some have carbohydrate side chains (glycoproteins)
- Hydrophilic
- Produce quick reaction in the body
8
Q
steroid hormones
A
- All made form cholesterol
- Different enzymes modify molecule to produce a variety of hormones
- Can’t dissolve in water
- Can dissolve in lipids
- Produce a slow response
