Human Physiology Unit One

Physiology Physiology is the study of the function of the body It investigates how the anatomy develops and how it works It emphasizes cause & effect relationships and mechanisms of action

Physiology The objective of physiology is to understand the normal functioning of cells, tissues, organs and organ systems It is studied on microscopic and chemical levels

Homeostasis Claude Bernard Walter Cannon

Homeostasis Homeostasis is the maintaining of a constant internal environment through the function of dynamic physiological regulatory mechanisms Homeostasis occurs despite fluctuations in the external environment

Homeostasis Homeostasis is maintained due to the intricate and delicate relationships between these regulatory mechanisms These regulatory mechanisms can be intrinsic or extrinsic

Homeostasis If any of these mechanisms break down, it causes a “ripple effect” which is indicated by becoming sick

Homeostasis Examples of homeostasis: + body temperature + blood pressure + heart rate + respiratory rate + blood particle levels

Homeostasis

Homeostasis vs. Stress Stress is any disruption of homeostasis that threatens physical or emotional well-being Stress is brought about by the breakdown of regulatory mechanisms

Homeostasis vs. Stress Examples of physical stress: + intense exercise + infection + injury + surgery + hemorrhage + pain

Homeostasis vs. Stress Examples of emotional stress: + grief + depression + anger + anxiety + guilt

Homeostatic Control Stimulus Response Integrating Center Sensor Effectors Stimulus Response

Homeostatic Model Upper Limit Range Set Point Lower Limit Sensitivity

Negative Feedback System Defends the set point Reverses the deviation Produces change in the opposite direction Dynamic process that maintains stasis

Homeostatic Example

Positive Feedback System Opposite of negative feedback Amplifies the deviation Action continues in the same direction If not controlled, this system would cause homeostatic imbalances

Definitions Basic Chemistry Acid – a compound that releases hydrogen (H+) ions in solution Base – a compound that releases hydroxide ions (OH-) in solution

Definitions Basic Chemistry Salt – an ionic compound that does not contain H+ or OH-, obtained from an acid/base reaction Buffer – a chemical system that resists large changes in pH by taking up or giving off H+

Acid-Base Reaction HCl + KOH KCl + H2O Cl- K+ H+ OH- Acid Base Salt Water HCl + KOH KCl + H2O Cl- K+ H+ OH-

Common Acids and Bases

pH – the measurement of the H+ concentration in solution

pH – the measurement of the H+ concentration in solution

Organic Chemistry The four types of organic compounds Carbohydrates Lipids Proteins Nucleic acids

Carbohydrates The general formula is CH2O The monomers are monosaccharides Functions: Provide energy Structural uses Examples: Plants - starch, cellulose, Animals - glycogen, chitin

Lipids Functional group – COOH- (carboxyl) The monomers are fatty acids and alcohols Functions: Storage energy Structural uses Regulation Protection

Lipids Examples: Fats (triglycerides) Phospholipids Steroids Waxes

Lipids The two types of fatty acids Saturated Unsaturated

Proteins Two functional groups – COOH- (carboxyl) and NH2- (amine) The monomers are amino acids Functions: Structural uses Regulation Protection Provide energy

Proteins Examples: Collagen Hormones Enzymes Antibodies

Nucleic Acids The monomers are nucleotides Functions: Heredity Nitrogen base Functions: aaaaaaaaaaa Heredity Protein synthesis Phosphate group Pentose sugar

Nucleic Acids Examples: Double stranded, double helix molecule Single stranded with three forms – tRNA, rRNA, and mRNA DNA RNA

Organelles of An animal cell Aaaaaaaaa aa Chromatin aaaaaaaaaa Aaaaaaaaaa aaaaaa aaaaaaa aaaaaaaaaaa aaaaaaa aaaaaaaa Aaaaaaaaa aaaaaa Aaaaaaa a Aaaaaaaaa Aa aa Aaaaaaaaa aaaa Aaaaaaaaa Aa aa aaaaaaaaaa aaaaaaaaa Aaaaaaa aaa aaaaaaaaaa Aaaaa aa aaa Aaaaaaaa aaa aaaaaaa aaaaaaa

The Cell Cycle The cell cycle is the process of growth and division found in most cells The functions of the cell cycle are growth, repair and replacement The cell cycle is divided into three segments

Interphase Cytokinesis Mitosis

Interphase G1 – organelles double S – DNA replicates G2 – proteins produced

Mitosis Prophase Metaphase Anaphase Telophase

Cytokinesis

The Cell Cycle The growth in size of a cell due to interphase is termed hypertrophy The growth in size due to the addtion of cells is termed hyperplasia In most cases, hypertrophy leads to hyperplasia

The Cell Cycle Two exceptions are muscle cells and neurons These cells go into a G0 phase and drop out of the cell cycle Therefore if they are damaged or destroyed they cannot be replaced