Circulatory System and Homeostasis

Week 1 Physiology

• Physiology studies the normal functioning of living organisms and their components.

Organ Systems and the Circulatory System

• The circulatory system, also known as the cardiovascular system, distributes materials by pumping blood through vessels.
• The circulatory system does not directly exchange materials with the internal or external environment.

Immune System

• Major components are the thymus, spleen, and lymph nodes

The Internal Environment

• Extracellular fluid (ECF acts as a buffer zone.
• The ECF needs to remain relatively stable.
• Intracellular fluid (ICF) is the fluid within cells.

Homeostasis and Mass Balance

• Homeasis depends on mass balance.
• The law of mass balance states that the amount of a substance remains constant if any gain is offset by an equal loss.
• Gain includes intake from outside and metabolic production.
• Loss includes excretion to the outside and metabolic removal.
• Mass flow is the rate of transport of a substance through the body.
• Excretion clears substances from the body.
• Clearance is the volume of blood cleared of a substance per unit time.

Homeostasis and Dynamic Steady State

• Homeostasis does not mean equilibrium
• Materials are constantly moving between two compartments in a dynamic steady state.
• Homeostasis maintains the dynamic steady state.

Disequilibrium and Adaptation

• Disequilibrium is an organisms ability to maintain constant internal conditions despite external conditions.
• Organisms quickly restore changed conditions to normal.

Control Systems

• Local and reflex control systems are involved in the body's response to stimuli.
• The components are an input signal, an integrating center, and an output signal.
• Feedback loops modulate the response loop.

Negative and Positive Feedback

• Negative feedback is homeostatic, it keeps systems at or near setpoints and stabilizes variables, e.g., insulin secretion.
• Positive feedback is not homeostatic and reinforces a response,e.g., childbirth.

Feedforward Control

• This allows the body to anticipate change.

Week 2, Energy and Work

• Energy is the capacity to do work.

Types of Work

• Chemical work: Making and breaking chemical bonds.
• Transport work: Moving ions, molecules, and larger particles, creating concentration gradients.
• Mechanical work: Moving organelles, changing cell shape, and contracting muscles.

Kinetic and Potential Energy

• Kinetic energy is the energy of motion.
• Potential energy is stored energy, such as in concentration gradients and chemical bonds.
• Energy can be converted from one form to another (transformation efficiency).

Chemical Reactions

• Reactants are transformed into products.
• Reaction rate is the speed at which reactants become products.

Free Energy and Activation Energy

• Activation energy gets reactions started.
• Free energy is the energy available to do work in a chemical reaction.
• Free energy change is the difference in free energy between reactants and products.
• Exergonic reactions release energy.
• Endergonic reactions require energy input.
• The net free energy change determines reaction reversibility.
• Activation energy is the energy required to initiate a reaction, bringing molecules into a position where they can interact.

Enzymes

• These proteins or RNA molecules that speed up the rate of chemical reactions.
• They are catalysts, reactants are called substrates.
• Isozymes that catalyze the same reaction under different conditions or in different tissues.
• Enzymes can be activated, inactivated, or modulated, and may require a co-factor to function
• Enzymes lower the activation energy of reactions.
• Denaturation occurs when an enzyme's activity is inactivated by heat or a change in pH.
• Phosphorylation is the addition of a phosphate group to a substrate, catalyzed by a kinase.

Hydrolysis and Dehydration Reactions

• Hydrolysis involves the addition of water while dehydration reactions produce water.

Addition, Subtraction, and Ligation Reactions

• Addition reactions add a functional group.
• Subtraction reactions remove a functional group like deamination removes an amino group.
• Amination adds an amino group.
• Transamination transfers an amino group.
• Ligation reactions or synthases join two molecules together.

Metabolism

• Catabolism is the energy-releasing breakdown of complex molecules into simpler structures.
• Feedback inhibition occurs when the product of a reaction decreases the activity of an enzyme.

Aerobic and Anaerobic Metabolism

• Aerobic metabolism yields 30-32 ATP per glucose molecule.
• Anaerobic metabolism makes two ATP.
• Catabolic pathways produce ATP through glycolysis in the cytosol, citric acid cycle in the mitochondria, and the electron transport system in the mitochondria.

Proteins Synthesis

• Proteins are crucial for cell function, exhibiting variability and specificity.
• Theyre composed of 20 amino acids arranged in sequences, where 3 bases (a codon) encode one amino acid.

Unlocking and DNA

• Genes, a regions of DNA, encode RNA through Transcription
• mRNA is translated into protein.
• DNA guides RNA synthesis using a template strand and RNA polymerase.
• Transcription factors are needed to activate a regulated gene.
• mRNA processing, including alternative splicing, allows for multiple proteins from one DNA sequence; exons encode proteins, and introns are noncoding segments

MRNA Translation, Diffusion and Channels

• mRNA translation links amino acids.
• Protein synthesis utilizes mRNA templates, ribosomes, and tRNA with anticodons.
• Protein sorting directs proteins to their destination via signal sequences.
• Diffusion is a passive process from high to low concentration down a chemical gradient, rapid over short distances, and directly related to temperature, inversely related to molecular weight and size, occurring in open systems or across partitions.
• Gated channels can be chemically, voltage, or mechanically gated.

Week 3 - Nervous System Organization

• CNS consists of the brain and spinal cord.
• PNS consists of sensory (afferent) neurons
• Efferent neurons consist of somatic motor and parasympathetic branches
• Autonomic nervous system divided into sympathetic (fight-or-flight) and parasympathetic branches, regulates involuntary body responses like muscle and glandular stimulation.

Electrical Signals and Potentials

• Graded potentials are used for short-distance communication characterized by variable strength.
• Action potentials (nerve impulses) are large depolarizations, are brief and used for long-range communication
• Concentration of Potassium is higher inside cells, while Sodium concentration is higher outside the cell.
• Sodium channels open and Sodium enters the axon when voltage gated

Cells and Immune response

• Ganglion is a cluster of nerve cell bodies in the PNS.
• Glial cells provide support for neurons: providing structural and metabolic support, neurons during growth
• Maintain homeostasis (schwan cells PNA's) provides myelan
• Microglia (CNS) - Specialized immune cells

Chemical Signs and Synapses

• Synapse is the place where an axon terminal meets
• Synaptic cleft is the space in between
• Neurotransmitters are reduced where cleft us
• Calcium signals the exocytosis of the neurotransmitters

protection of brain structure

• Mainly produced by the choroid plexus epithelium & ependymal cells of the ventricles
• Choroid plexus transports nutrients from bloodstream to the of the ventricles Structures that protect the brain are
  • Cranium-Dura matter (cranium covering)
  • Subarachnoid space space below mater
• The blood-brain barrier is fromed from capillary endothelial cells
• Spinal cord
• Dorsal horns contain visceral & somatic SENSORY nuclei
• Lateral horns contain visceral MOTOR nuclei
• Ventral horns contain somatic MOTOR nuclei
• Divisions of white matter: columns of tracts that take sensory information to brain, carry motor signals from brain,and tracts stay in the cord

Communicating Between Brain Hemispheres

• Corpus callosum allows communication between the two hemispheres of the brain

Chemo and Mechano and Smells

• Chemoreceptors respond to chemical ligands or stimuli such as oxygen and taste, smell/odor
• Mechanoreceptors respond to mechanical energy pressure such as cell swelling, sound/hearing
• Chemoreception-Smells and tests
• Olfactory bulb sends olfactory information
• Odor binds to receptor

Senses

• Somatic senses (Spacinian deep touch, Merkel fine gentle touch)
• Taste is combo of 5 sensations and cells

The Ear

• External Ear Pinna, tube, tympanic membrane where ear ends
• Middle Ear Amplifys
• Inner Ear Semicircular, equilibrium canals (vestibular) window, Hearing (cochlea in oval/round windos)

Equilibrium vs Healing

• Sounds is Stimulated by healing cochlea
• Equilibrium is Stimulated by inner ear
• They stumulate in the vestibulocochlear and using hair cells.

Cochlea

• contains duct from organ of corti
• attaches to the stereocilia to hear

Equilibrium (Chambers)

• Series of connected that provides info about movement and position
• Organes sense linear

Ear organs

• Maculae sense motion
• The cupula in the ampullge rotation

The Eye + vision

• The three steps are
• Light - Eye focuses on light
• Photos transduce signals Path of light flow Cornea , Vitreous, retina Affected vision if deficient

Week 4 - Adrenal Gland

• Composed of that secrete mainly epinephrine
• outer area secrets hormones
• Main that secreted that suppresses , influences brain function decreased if you can’t convert to glucose
• of, and it will not increase levels

Thyroid

• Iodine, symport
• with that brings into follicle
• TSH increases Thyroid and GH increases GH calcium and excreation and activity

All Chemo reaction

• pathways extracting energy and excess and work that’s used later
• only does these

glycogen storage the brains source glucose is that are needed with glucose being small

• large

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Explore the circulatory system's primary functions, its relation to physiology, and its role in homeostasis. Understand reflex control systems, feedback mechanisms, and the importance of extracellular fluid in maintaining balance within the body.