human physiology

Structural organization & Body systems

6 levels

• chemical level: involves basic units of matter (atoms+molecules)

E.g transfer of energy through chemical matter

• cellular level: comprises individuals cells, vary in type and purpose

E.g red blood cells carrying oxygen

• Tissue level: organization of cells with similar structures and functions

e.gmuscle( contracts for movement

• organ level: different types of tissue working together to perform specific functions

E.g stomach+the kidneys

• system level: consists of a lot of organs that collaborate to carry out broader physiological functions

  (Consists of)→ hormone-producing glands and hormone producing cells in numerous organs

E.g cardiovascular system/ muscular system

• organismal level: the entire living organism (all systems working together)

BODY SYSTEMS

Most focus

• muscular

• Nervous

• Cardiovascular

• Respiratory

• Endocrine

NERVUSE SYSTEM

(Consist of) → brain , spinal cord, nerves

Function: generate action potentials to regulate body’s activities (interprets changed to environment

ENDOCRINE SYSTEM

Function: regulates bodies actives by releasing hormones

RESPIRATORY SYSTEM

(Consists of)→ lungs and air passageways

Function: transfers carbon dioxide form blood and exhaled air

CARDIOVASULAR SYSTEM

(Consists of) → blood, heart and blood vessels

Functions: blood carries oxygen and nutrients to cells

MUSCULAR SYSTEM

(Consists of) → skeletal muscle tissue s

Function: helps with body movements + maintains posture

ENERGY SYSTEMS

ATP/PC

-Immediate energy supply proffered fuel=PC stores last < 10s

Anaerobic system

-Intermediary energy supply → preferred fuel= glycogen

Basic Life processes

Metabolism: susms all chemical processes

Responsiveness: Bodies ability to detect and respond to change

Movement: Motion of the whole body

Growth : increase in size of cells

—> If one of these stops working it can lead to death

Aerobic system

-sustained energy supply → preferred fuel = fats & glucose

Differentiation: development of a cell from an unspecialized cell to a cell which is specialized

Reproduction: Formation of new cells by the process of cell division

Homes = sameness ( HOMEOSTASIS)

Stasis = standing still

—> body likes to be static and tightly regulated

Homeostasis : the condition of equilibrium ( balance) in the body’s internal sentiment due to constant interaction of the body’s numerous regulatory processes

A dynamic conditions

• balances input with output

—> making sure it’s not too sweet , sour or thick

Fluid within the cell = intercellular fluid

Fluid outside body cells = extra cellular fluid

ECF between cells of tissues = interstitial fluid

(Important )

— what regulates things out of cells

CONTROL OF HOMEOSTASIS

— constantly disrupted internally and externally e.g physiological factor or psychological factor

Disruption can be prolonged

Nervous system and endocrine system =work together to regulate homeostasis

FEEDBACK either negative or positive

NEGATIVE : bringing the response back to normal e.g if the body is hot the body will sweat to cool down (temperature)

POSTIVE: reinforce the change that is detected e.g labor , blood clotting

Afferent parhway : transmits input to the control center (sensory system )

Control center (brain ) : process information ,assess input from receptors

PHYSICAL ACTIVITY & HOMEOSTASIS

→ negative feedback responses

adaptive responses : body needs to shift to match the intern energy demands

Increase breathing = getting more oxygen —> increase respiration

Heart rate and oxygen: when having an increase heart rate allows for greater muscles energy requirements

INORGANIC & ORGANIC COMPOUNDS

Chemical elements (Major elements)

• oxygen

• Carbon

• Hydrogen

• Nitrogen

Chemical reactions are the foundation of all life processes —> each chemical reaction involves energy changes

→ potential energy

→ chemical energy → Electrical energy

→ kinetic energy

Types of chemical reactions

1.Anabolism (synthesis reaction): two or more atoms, ions or molecules combine to form new and larger molecules e.g DNA synthesis

1. Catabolism( Decomposition reaction): Spilt up large molecules into smaller atoms,ions or molecules e.g Lipolysis

Chemical elements

( organic & inorganic)

• inorganic compounds lack carbon and are structural simple

• Organic compounds always contain carbon and often have hydrogen

INORGANIC COMPOUNDS- Water

→ Solvent: Dissolves waste products, which allows them to be flushed out of the body in the urine

→ Chemical reactions: Synthesis reactions produce larger ,moelcules and release water as a product

→ Lubricant: Facilitates organ movement, joint function and digestion

→ Thermal properties: Able to absorb and release a significant amount of heat with minimal temperature change

SALTS, ACIDS & BASES

Salts (important for bodily fluids)

• Salts are important parts of fluids in our body like blood and lymph, they carry out essential chemicals that out body needs to work properly

Acids

-Dissolve in water and release hydrogen ions (H+) and negativity charged anions

Bases (proton donors)

-dissolve in water and release hydroxyl ions (OH-) and positively charged cations

(Proton acceptors)

Acid-Base Balance

• The more H+ in a solution = more acidic

• The more OH- in a solution = more basic

• PH gradients are essential for moving fluids like blood and maintaining cellular functions

ORGANIC COMPOUNDS ( always contain carbon)

→ allows them to carry out complex functions e,g carbohydrates, proteins ,lipids

IMPORTANCE OF CARBON

-Can form four bonds with other elements ( can create complex molecules with diverse structures

-they are extremely stable

Ability or form polymers (Large molecules made up of repeating units

KEY ORGANIC COMPOUNDS

• Carbohydrates: provide easily used source of cellular food (soluble to water)

• Lipids: provide energy, insulation and protection

• Proteins: play a role in growth, repair and maintenance of body tissues, immune function and cell differentiation

• Nucleic acids: DNA→ inherited genetic material inside cells + RNA → relays instructions to guide cell synthesis

ATP: transfers energy liberated in exergonic catabolic reactions to power cellular activities that require energy

ENERGY PATHWAYS FOR EXERCISE

• nuritent conversion to energy

→ carbs fats and proteins are nutrients that the body covets unto ATP

• Fuel sources for expertise

→carbs are the primary fuel for moderate to high intensity exercise

→ fats can sustain low intensity exercise for extended periods

• Metabolic pathways

→ATP-CP for short burst

→ glycolysis for high-intensity short duration exercise

• Changing fuels sources

→ body shifts from fat to carbohydrate metabolism as exercise intensity increases due to increase oxygen demand

WEEK 2

Human physiology fundamentals II

The plasma membrane

• lipid bilayer ( double- layered wall)

• Protein ( a gatekeeper, controls what goes in and out of the cell)

• Carbohydrates ( acts as a name tag , allows cells to recognize each other)

Plasma membrane function

-barrier controls : allows certain substances to enter and exit

-message reception: acts as receptors and receives signals

-supportive wall:serves as a sturdy barrier matins cells shaped

-Cell ID:helps recognizes from foreign cells

Membrane proteins: determines the function a cell can perform (embedded into the lipid bilayer) - ( peripheral proteins are loosely attached)

→ membrane fluidity: flexibility and mobility of thee lipid molecules (movement of protein within the membrane

(Temperature = the cooler the environment the less fluid the membrane is )

→ membrane permeability: ability of the membrane to allow substances to pass through

BOTH ESSENTIAL FOR REGULATING CELLULAR FUNCTIONS

THE CYTOPLASM

→ All cellular contents between the plasma membrane and the nucleus

(Two primary components)

• the cytosol

• Organelles

Ribosomes

-carry out mRNA instructions to build cellular material

Lysosomes

-carries dygestive and hydrologic enzymes + helps recycles worn-out cell structures

Endoplasmic reticium

-aids in removal of substances + synthesis glycoproteins (Rough ER) - smooth ER :sythesis fatty acids & steroids

Cilia & flagella

-moves fluid along cells surface

Mitochondria ( powerhouse of the cell)→ helps regulate the lifestyle of the cell (can self replicate in size and number)

The nucleus : Most prominent feature of a cell (determine cell functions and responsibilities)

3 primary function

• controls cellular structure

• Directs cellular activities

• Produces ribosomes

Transport across the plasma membrane

( passive process of transport)

Diffusion:(key element for the plasma membrane) →when the random mixing of particles in a solution occurs (high concentration to low concentration

-factors that influence the diffusion rate across plasma membranes

• steepness of the concentration gradient

• Temperature

• Surface area

• Diffusion distance

Simple diffusion: substances move freely through the lipid bilayer e.g oxygen+carbon dioxide

Facilitated diffusion: an integral membrane protein assists a specific substance across the membrane (either carrier-mediated or channel mediates

Osmosis:water moves through selectivity permeable membrane e.g water (only substance)

(Active processes of transport )

→ uses energy to move substances from low to high concentration

primary active transport: directly uses energy to power the movement of substances across the plasma membrane

• Secondary active transport: Indriectly uses energy to power the movement of substances across the plasma membrane

→ Antiporters: carry two substances across the membrane in opposite directions

→ symporters: carry two substances across the membrane in the same direction

Transport in vesicles

• endocytosis: vesicles detach from the plasma membrane bringing material into cells

(3 TYPES)

→ Reeptor-mediates endocytosis

→phagocytosis

→bulk-phase endocytosis

• exocytosis: merging of vesicles within the plasma membrane ( realease material)

(TWO TYPES)

→ cells that release digestive enzymes + hormones

→ nerve cells that release neurotransmittersTWO TYPES)

→ cells that release digestive enzymes + hormones

→ nerve cells that release neurotransmitters

(TYPES OF TISSUE) → 4 types

• Epithrlial tissue: cels that are arranged in contunous sheet( multiple layers) → lines body cavities

—> e.g skin

• connective tissue: it binds,strengthens and supports, protects,a transport system,stores energy,maintains source of immune response

Connective tissue cells

1. Proper→ loose→ adipose (FUNCTION): provides reserve food fuel undulates against heat loss

2. Blood (function): transports respiratory gases nutrients,wastes

3. Cartilage→hyaline(function):supports and reinforces, serves as a cushion

• muscular tissue:produces movement ,maintains posture, generate heats

→ three types

1. Skeletal

Function: movement, posture,heat production

Location: attached to bones by tendons

1. Cardiac

Function:pump blood to all party’s of the body

Location: heart wall

1. Smooth

Function: motion of blood vessels airways

Location:walls of hollow internal structures

→ nerve cell

• nervous tissue (two types

Generate and conduct nerve pulses

→Gilal cells

Each organ is composed body systems are composed of 2 or more tissues

E.g heart→ made up of cardiac muscle tissue,connective tissue ,epithelial tissue

CARDIAC MUSCLE tissue → made up muscle fibers within the cell

Central dogma of molecular biology: examples the flow of genetic information

RNA= Helps translate and transcribe info

DNA into DNA = Replication

DNA into RNA = Transcription

RNA into protein = Translation

DNA → RNA → protein

Base pairing

(A = T )

(C = G)

• DNA polymerase: unwinds the DNA

• Topoisomerase: unwinds DNA

• Helicase: breaks apart DNA

(GENE EXPRESSION PART 2)

A gene: function unit of DNA sequences that encode for specific proteins or molecules

Encode proteins = coding genes

Encode molecules=non-coding genes

(Genes need to be transcribed(copied) and translated (decoded into proteins

Parts of a gene

Exon → codes for a specific proteins (protein coding region)

Intron → non protein coding region

Promoter region → initiates or kickstarts our transcription process

TRANSCRIPTION

DNA into messagenger RNA(mRNA) = copied from one language into another

3 steps

Initiation → RNA only erase attached to promoter region of DNA, guided transcription factors

Elongation → New RNA molecules get added complementary to the DNA template strand

Termination → Stop signal regulate by Rho proteins or CG sites

RNA processing

• the 5’cap and poly-Atail helps stabilizes the mRNA strand

TRANSLATION

• sequence of amino acids make up proteins

→ start & stop codon

3 steps

Initiation: ribosomes assemble around mRNA,tRNA binds to start codon

Elongation:mRNA is read one codon after another and amino acids matching the codon get added by tRNA

Termination: real ease factor recognized stop codon,terminate reaction

At transcription level

→ we have promoter regulation

At RNA processing

→ splicing + degrading of RNA

At Trnalsation

→ start of translation,ribosomes assemble

At post-Translation

→ processing,modification and stability of proteins

Cell signalling

Cell signalling: a way for our cells to communicate (allows to response to changes and regulate cell behavior)

Communicate → response to intracellular changes → respond to extra cellular environment → regulate cell behaviour

Ligand: signal molecule E.g gases,lipids,hormones

→ interacts with a cell by binding itself to a receptor

• As the ligand and receptor join together this creates a signal transduction pathway

TYPES OF SIGNALLING

Contact dependent: requires direct contact( through gab junctions)

Autocrine: relapse of signals from a cell that act on itself

Paracrine: relapse of signals that can travel short distance to target cell

Synaptic: relapse of neurotransmitters across synapse(the distance between the neuron and the cell) to target cell

Endocrine: relapse of Hermes into the circulatory system to target distant cells

STEPS OF CELL SIGNALLING

Reception→ signal molecule binds receptor

• can only bind to a certain receptor

• May change shape when its bound to its ligand

Transduction → intracelualr singalling proteins distribute the signal

Response → effector proteins initiate a response(can be varied) to the signal

MAIN CLASSES OF RECEPTORS

(Four main classes)

1. ion channels receptors: usually in rapid synaptic signalling

2. G-Protein-coupled receptors: associate with trimeric ( 3) G proteins

3.emzyme-coupled receptors : Have enzyme activity or associate with an enzyme

4.intracellular receptors

Transduction( signal relay)

• involves intracellular signalling molecules (secondary messages)

• Regulated by molecular switches (switch from inactive to active)

• Important for signal amplification

RESPONSE

-timing and persistence (response can be quick or slow

-sensitivity and range: response can be triggered by low or high concetration

Integration and coordination Response may need combination of signal activation and inhibition

Complexity in signal regulation

• phosphorylation: adding a phosphate is turning it on and removing one is turning it off

(protein kinase)→ is what is adding that phosphate group

(Protein phosphate)→ removes phosphate groups

• GTP binding:The (GEF) Guanine nucleotide exchange factor turn on the protein & the GAP tuns it off by breaking down the GTP

Scaffold proteins → help organize the process ( have interaction domains , brings together all the molecules to help it work properly)

Postive feedback → response to a signal promotes further signalling ( keeps the signal going)

Negative feedback→ a response to a signale that stops or inhibits further signalling (stop to reduce)