BME-HUMAN ANATOMY-1

MOLECULES, CELLS, TISSUES

THE ORDER OF COMPLEXITY• ANATOMY – is the scince, which

study macrostructure of human body.

• Organism consists of

Organ systems <= Organs <=

Tissues <= Cells <= Molecules

<= Atoms (p. 13)

• Cellular interaction is mainly chemical. The sum of all chemical reactions is called metabolism.

• Metabolism consists of katabolism & anabolism.

• Human body has capacity for restoration. Inner equllibrium is called homeostasis.

• The body’s ability to detect the chages and activate its mechanisms to oppose that changes is called negative feedback.

• (p.17-18) Body reaction to heat by vasodilation and to cold by vasoconstriciton are examples of that feedback

• (p.19) Positive feedback occurs when certain changes lead to more changes in the same direction, as in case with childbirth

Chemical structure of human body

• Our body consists of 24 out of 91 naturally occuring on the earth elements.

• Six of them account the 98.5% of body weight: oxygen, hydrogen, carbon, nitrogen, calcium & phosphorus

• The following 0.8% of body weight comes from sulfur, potassium, sodium, chlorine, magnesium & iron.

• The rest of 12 elements account for the last 0.7%• Other natural elements without physiological role only

harm human body, like lead or mercury.

Macromolecules

• Elements comprise molecules & macromolecules like carbohydrates, lipids and proteins.

• Carbohydrates are organic compounds built of monosaccharides (e.g. glucose, fructose, galactose), disaccharides (glucose+galactose=lactose), oligosaccharides (3 -20 monosaccharides) and polysaccharides (glycogen, starch, sellulose).

Carbohydrates

• …are quickest source of energy• …can conjugate with proteins into

glucoproteins, i.e. mucus of respiratory & digestive tracts) and proteoglycans (known as mucopolysaccharids), i.e. The gel, which bounds cells together, lubricate the joints and is part of cartilage

• …can conjugate with glycolipids, i.e. part of cell membrane

LIPIDS - definition

• Lipids are hydrophobic organic molecule, usually composed only of carbon, hydrogen, and oxygen (p.63)

• Lipids are less oxidized than carbohydrates, and thus have more calories per gram(1gr=>9cal).

• It is difficult to generalize about lipids; they are much more variable in structure than the other macromolecules

LIPIDS - classification• Fatty acids Precursor of triglycerides; source of energy

Saturated & unsaturated fatty acids• Fat-soluble vitamins (A, D, E, K) Involved in a variety of functions

including blood clotting, wound healing, vision, and calcium absorption• Triglycerides Energy storage; thermal insulation; filling space;

binding organs together; cushioning organs • Phospholipids Major component of cell membranes; aid in fat

digestion• Eicosanoids Chemical messengers between cells• Steroid hormones Chemical messengers between cells• Bile acids Steroids that aid in fat digestion and nutrient absorption• Cholesterol Component of cell membranes; precursor of

other steroids“Good” cholesterol HDL & “bad” cholesterol LDL

PROTEINS (p.66,fig.2.24)- definition

• Protein is a polymer (i.e. chain) of aminoacids (aa).

• Peptide is the molecule, composed of 2 or more aminoacids.

• Oligopeptide is a chain of 10-15 aminoacids. E.g. oxytocin is 9-aa olygopeptide

• Polypeptide is a chain with more than 15 aminoacids. E.g. ACTH is polypeptide of 39 aa.

• Protein is polypeptide of 50 or more aa

PROTEINS – structure (p.66)

• Proteins have coiled structures, which is of paramount importance: even slight changes in their shape destroy its function.

• Protein molecules have four levels of complexity, from primary through quaternary structure (fig. 2.25).

PROTEINS – function (p.67)

• …provide with structure –e.g. keratin, collagen• …are some hormones in cell-to-cell

communication• …form channels in cell membrane for

trnasportation• …metabolic enzymes, catalysts of chemical

reactions• …are antibodies, i.e. Part of immune system• …provide with movement-e.g. actin, myosine

NUCLEOTIDS & NUCLEIC ACIDS

• ATP – adenosine triphosphate – is most well-known nucleotide, is the major energy-ransfer molecule(p.72, fig.2.30)

• Nucleic acids are polymers of nucleotids, most well-known are DNA & RNA

CELL – basic components

• Cell membrane – made of proteins and lipids• Cell nucleus – is the DNA, i.e. genetic control

center of cellular activity.• Cell cytoplasm – compound between

membrane and nucleus, filled with fibers, tubules, cytoskeleton (supportive protein) and organelles (p.83, fig.3.5).

TISSUES

Definition: tissue is a group of cells, united to carry out a specific function.

There are 4 types of tissues:• Epithelial tissue• Connective tissue• Nervous tissue• Muscular tissue

TISSUES – epithelial tissue

Definition: is a group of layers of cells that cover organ surfaces, form glands, and serve for protection, secretion, and absorption

Forms of epithelial tissue:• Epidermis• Inner lining of digestive & respiratory tracts• Liver and other glands

TISSUES – connective tissue

Definition: is the body matrix ,specialized in support, binding, and protection of organs

Types of connective tissue:• Tendons and ligaments• Cartilage and bone• Blood

TISSUES – nervous tissue

Definition: is the group of cells, which generate & transmitt signals to other cells.

Parts of nervous tissue:• Brain• Spinal cord• Nerves

TISSUES –muscular tissue

Definition: is a group of of muscle cells specialized in contraction.

Types of muscular tissue: • Skeletal muscles • Myocard (heart muscle)• Smooth muscles (walls of the vessels, bronchi