Human Body Systems: Excretion, Digestion, and Immunity

Human Body Systems and Excretion

Absorption vs. Assimilation

Compare and contrast

Absorption and Assimilation

• Similarity: Both involve nutrients—absorption transfers them into the bloodstream, and assimilation uses them in cells.

• Difference: Absorption happens in the digestive system; assimilation occurs in tissues.

Digestion vs. Nutrition

Digestion and Nutrition

• Similarity: Both are essential for energy and growth—digestion breaks down food, and nutrition provides the substances needed for this process.

• Difference: Digestion is the physical and chemical breakdown of food, while nutrition involves obtaining and using nutrients for the body’s needs.

Diffusion vs. Endocytosis

Diffusion and Endocytosis

• Similarity: Both are processes that transport substances into or within cells.

• Difference: Diffusion is passive and moves molecules down a concentration gradient, while endocytosis is active and engulfs substances into the cell using energy.

Digestive Enzymes

Knowledge of digestive enzymes:

(GRAPH)

A: Proteases, because the PH is very low, near 2. Mainly secreted into the stomach (gastric juices). Gastric juices contain HCL which creates very acidic conditions. PH 2 is the optimal condition for proteases to break down proteins into amino acids.

B: Amylase, because it is near 7. Mainly secreted into the mouth (salivary glands --> saliva). Saliva creates a neutral PH (PH 7), which are the optimal conditions to break down starch (polysaccharidic) into glucose (monosaccharide).

C:

(GRAPH OF MASS % VARIATION)(GLUCOSE CONCENTRATION)

1. The mass of the potato increases until the solutions reach about 0.3 M. At 0.0 M potato’s mass has increased by a 10%. We can see how the mass variation decreases gradually. This has happened because the water potential in the solution is higher than the water potential inside the potato's cells; this process is called osmosis.

2. There has been no mass difference because the water potential in the solutions is the same as the water potential in the potato's cells. This means that there is no water potential gradient; this process is called Isotonic.

3. The mass of the potato has decreased because the solutions where they were immersed in are hypertonic. This means the cells water potential of the solution. There has been a mass % variation of 14% between 0.4 and 0.1 M

Body's Barriers

Unspecific Barriers:

1. Skin 2. Tears (Gland: lysozyme) 3. Ears (Waxy layer: lipids) 4. Nose (Hairs and mucus) 5. Ciliated epithelium

Specific Barriers:

1. Endocytosis 2. Bacteria 3. Lysosomes 4. Golgi’s 5. Glycoproteins 6. Exocytosis 7. APC’S -> Glycoproteins (Ag)