Introduction to Physiology

Introduction to Physiology

• Physiology is a biology branch focused on understanding living things' mechanics
• It examines mechanisms from cell function at the ionic and molecular levels
• It considers the integrated behavior of the whole body
• It analyzes the influence of the external environment

Structural Organization Levels

• Chemical level involves atoms and molecules
• Atoms are the smallest units
• Two or more atoms form a molecule like protein or water
• Cellular level is where cells are made of molecules
• Tissue level comprises similar cell types
• Organ level consists of different tissue types
• Organ system level has different organs working closely

Cell Physiology

• The cell serves as the structural and functional unit of life
• Every living thing has cells: bacteria, protozoans, fungi, plants, and animals
• These are main groups, known as Kingdoms
• Some organisms are unicellular, like bacteria and protozoans
• Animals, including humans, are multicellular

Specialized Cells

• Approximately 200 kinds of specialized cells exist in the human body
• Tissues are formed when identical cells organize together, like muscle tissue
• Organs form when different tissues organize for a common purpose, like the stomach

Prototypical Cell: Cell Membranes

• Cell membranes (plasma membrane) surround the protoplasm (semi-fluid living matter)
• It's a biological membrane of a phospholipid bilayer, proteins, lipids, and carbohydrates
• Cell membranes act as the cell's boundary
• Separates intracellular components from external
• It regulates internal metabolic events

Cytoplasm and Cytosol

• Cytoplasm describes all material between plasma membrane and nucleus
• Composed of cytosol and organelles
• Cytosol is the aqueous component where organelles float, excluding the nucleus

Organelle Types

• There are two types of organelles: Membrane-bound and Non-membrane bound

Membrane-Bound Organelles

• Includes rough/smooth endoplasmic reticulum, Golgi apparatus, lysosomes, and mitochondria
• Endoplasmic Reticulum (ER) contains parts of the membrane that shares with the nucleus
• Rough ER has ribosomes, used for protein production
• Smooth ER produces vital lipids (fats)
• Mitochondria are oval-shaped is the "powerhouse" of the cell
• It transforms molecules like glucose into ATP through cellular respiration

Non-Membrane Bound Organelles

• Includes ribosomes, cytoskeleton, cilia, and flagella
• Ribosomes are protein factories composed of two subunits
• They float freely in the cytoplasm or are embedded in the ER
• Two types of RNA provide templates and instructions for ribosomes synthesize proteins
• Synthesized proteins are essential for cell survival
• The cytoskeleton is a network of filaments and fibers in the cytoplasm of eukaryotic cells
• It is responsible for cell shape, organization, locomotion, and movement of organelles within

Nucleus

• The nucleus is the control center of the cell, housing DNA
• It's the largest intracellular membranous organelle
• Nuclear membrane: A semipermeable membrane around the nucleus
• It regulates the transfer of compounds in and out of the nuclei
• Nucleoplasm: A gel-like medium where nuclear components exist
• Nucleolus: Involved in protein transcription
• Chromatin network: A fibrous network where genetic materials are deposited

Homeostasis

• Homeostasis refers to the body's mechanism to maintain a stable internal environment
• Occurs despite external changes
• Physiological parameters like temperature, pH and glucose are regulated
• Regulation ensures these parameters remain optimal for cellular function

Thermoregulation

• Thermoregulation is the regulation of body temperature
• It’s a vital aspect of homeostasis
• Maintaining a stable internal temperature (around 37°C/98.6°F) allows enzymes to function
• Stable temperature also allows metabolic processes to occur properly

Thermoregulation Defined

• The human body constantly interacts within its environment, where external temperatures vary
• The body is constantly adjusting its temperature to maintain homeostasis
• Involves heat regulation and other mechanisms

Heat Production and Loss

• The body primarily generates heat through metabolic activities
• Examples include muscle contractions, digestion, and cellular processes
• Heat loss occurs through radiation moving away from the body
• Convection transfers body heat to surrounding air or water,
• Conduction is direct heat transfer through contact
• Evaporation occurs when sweat evaporates from the skin

Thermoregulation Through Sweating

• Sweating occurs when the body overheats due to exercise or hot conditions
• Sweat glands produce sweat
• As sweat evaporates, it absorbs body heat, cooling the body down

Thermoregulation Through Vasodilation

• In response to heat stress, blood vessels near the skin dilate
• Dilation increases blood flow in promoting heat loss
• Vasodilation helps the body transfer more heat to the environment

Thermoregulation Through Vasoconstriction

• In cold conditions, blood vessels constrict
• Constriction reduces blood flow to the skin and extremities
• Vasoconstriction serves to conserve heat in preventing heat loss

Thermoregulation Through Shivering

• Shivering is an involuntary muscle activity that generates heat
• Rapid muscle contractions burn energy and produce heat

Heat Stress and Its Effects

• Heat stress occurs with exposure to high temperatures for sustained periods
• Body temp increases, leading to heat exhaustion or stroke
• Symptoms: excessive sweating, dehydration, dizziness, fatigue, and nausea

Cold Stress and Its Effects

• Cold stress occurs when the body is struggling to maintain body heat with low temperature exposure
• If body temperature drops too low, hypothermia can occur
• Hypothermia is when the core temperature falls below 35°C (95°F)
• Leads to organ function impairment, confusion, and even death

Homeostasis Regulation Experiment

• Objective: Observe how the human body regulates homeostasis during temperature changes
• Materials: Hot and cold water bowls, thermometer, stopwatch, towel

Homeostasis Procedure - Initial Observation

• Sit and rest
• Record hand temperature with a thermometer (if available) or general sensation
• Exposure to Hot Water: Put one hand in hot water for 1-2 minutes, record temperature (if measurable)

Observation Records in Experiment

• Record how hand feels (warmth, tingling, redness), noting skin tone or blood flow changes

Cold Water Exposure

• Immediately after hot water, put same hand in cold water for 1-2 minutes

Observation Records in Experiment

• Record any changes in the temperature or sensation of your hand
• Note any visible signs such as paleness, redness, or shivering

Recovery

• Take hand out of water, allow it to naturally return to room temperature
• Observe how long it takes for your hand to feel "normal" again

Observing Results

• In hot water: dilation releases extra heat, reddening skin,
• In cold water: constricted vessels conserve body heat, resulting in pale skin
• During hand recovery: the hand should gradually return to normal temperature through internal regulation

Selective Permeability Factors

• Membrane is made up of lipid bilayer and proteins
• In animal cells, the membrane safeguards the cells internal contents

Permeability

• Phospholipid bilayer that explains the water-loving hydrophilic head and water-fearing hydrophobic tail
• Hydrophilic heads face outside where water molecules are found
• Hydrophobic nonpolar tails positioned inwards towards one another
• Plasma membranes have a selective permeability, controlled by its phospholipid bilayer

Additional membrane component

• Cholesterol increases the animal membrane’s fluidity
• Proteins are scattered forming a mosaic pattern, integral, peripheral, transport and receptor proteins.
• Carbohydrates are combined with proteins or phospholipids, known as glycoproteins or glycolipids, aid in cellular recognition

Passive Transportation

• Passive transportation is non ATP energy use, ions travel to low gradient concentration
• Simple diffusion substances move high to low concentration and no carrier molecules. Example Oxygen and carbon are easily diffused.

Facilitated Diffusion

• Facilitated Diffusion uses channel proteins so molecules can enter from low to high concentration follows gradient
• Experiment uses materials dropper, food color, ink , hot and cold water. By using dropper mix in cup take note of time and observe result

Solute Diffusion & Dialysis Tubing Diffusion

• Requires a dialysis bag beaker, glucose add water until soft. Cut tubing 40cm, close with2 knots.
• Add four full drops of starch to the bag, hold and mix rinse the distillated water.

Cell Membrane

Osmosis Transport

• Semi permeable that water molecules go to low solvent concentrations

Osmotic Environments

• Hypotonic reduces solute concentration inside the cell
• Isotonic are a medium with same solute concentration
• Hypertonic greater relative cytoplasmic concentration when the cell water diffuses and goes through the loss of water

Active Transport

• Active Transport across the membrane ions expended energy through the gradient
• High concentration goes to low concentration using transport protein like sodium

Endocytosis

• Endocytosis includes the exit and enter of vesicles and large particles, like Phagocytosis

Osmosis and Tonicity Experiment

• Four dialysis bags, 20ml solution of %20 glucose, 10% NACL, %40 Glucose, with 40% of sucrose. In a volume equal amount in beaker.

Procedure

• Each bag label one to for filled with solutions of glucose, and sucrose. After 30 sec the measure the weight and surface.

Cardiovascular System Function

• This system provides blood supply that is under stimuli of the vessels arteries, heart, etc
• The regulation changes volume, changes adrenaline such as hormone electrolytes.

Blood Pressure

• Results from the heart pumping circulatory pressure in systolic pressure of contraction and diastolic pressure for relaxation. Measurements are millimeters of Mercury. Hypo and hypertension is considered

Systolic And Diastolic

• Diastolic fills relaxes and refills pressure returns to around 60mg, it increases the heart pressure of 100-140mg

Measuring Pulse

• Automatic measure with arm tighter, take the reading when cuffs release air automatically

Measurement

• Push in the air to tighten and pressure that follows the release of the air through brachial when you hear it go silent
• Blood may be shown through a result with heartbeat is first. Normal blood must be between 120 or less systolic pressure with higher diastolic higher than 80 and or 120.