Unit 3

• Unit 4 covers Biological Systems in the 2023-2024 academic year.
• The timeframe is 7.
• Global context revolves around orientation in space and time.
• Key concept is systems
• Function and Environment are the related concepts.
• Biological systems uphold a system of structure and function.
• The purpose is exchange & interaction between organisms and the environment.
• Inquiry questions explore structures for nutrient exchange, environmental adaptation, and homeostasis.

Biological System

• A tissue is a group of equivalent cells performing allied functions.
• An organ consists of multiple tissue types collaborating for specific functions.
• An organ system is a collection of organs performing body functions.
• Orientation exists through the relationship of cells, tissues, and organs.
• Organs include different tissue types, with one main tissue for main function and others providing support.

Levels of Organization

• The text lists subatomic particles, atoms, molecules, macromolecules, organelles, cells, tissues, organs, organ systems, organism

Vital Organs

• The five vital organs for human survival are the heart, brain, kidneys, liver, and lungs.
• The heart’s primary tissue is cardiac muscle, which pumps blood and is unique to the heart.
• The heart also uses both nervous and connective tissues to support its function.
• The heart is located centrally in the chest, is responsible for blood flow, delivering nutrients, and removing waste.
• The brain, in the head, is responsible for thoughts, memories, perceptions, and feelings.
• The two kidneys, located in the abdomen, filter blood to produce urine, which removes blood waste.
• The liver, on the right side of the abdomen, filters blood, and makes proteins for blood clotting.
• The two lungs, in the upper chest, exchange oxygen and dioxide with the blood.

Human Organ Systems

• Organs form systems; a clear difference exists between male and female reproductive systems.
• A goal of body systems is to maintain a stable internal environment.
• Homeostasis is self-regulation, maintaining stability under optimal conditions for survival.

Integumentary System

• Organs include skin, hair, and nails.
• The skin is the largest organ in the body.
• It protects the body and is the site of receptors.
• It is the first line of defense and also helps regulate body temperature and eliminates wastes through sweat.

Skeletal System

• Consists of bones, joints, and teeth
• Bones in this system connect via tendons, ligaments, and cartilage
• The system supports the body and enables movement when paired with the muscular system.
• Bones also protect internal organs, store calcium, and produce blood cells.

Muscular System

• Consists of three muscle types.
• Skeletal muscles allow for voluntary movements.
• Smooth muscle controls involuntary movements.
• Cardiac muscle controls the involuntary heart beat.

Nervous System

• Includes the central (brain and spinal cord) and peripheral nervous systems.
• Regulates voluntary and involuntary actions.
• Its functions include sensory information.

Endocrine System

• The glands secrete hormones into the bloodstream
• Hormones control metabolism, growth, and sexual development.
• The pituitary gland regulates other endocrine glands.
• Other glands are the pancreas, thyroid, and adrenal glands.

Cardiovascular System

• Consists of the heart, blood, and blood vessels (arteries, veins and capillaries).
• The transport of oxygen and nutrients is the main function of the cardiovascular system.
• The system aids temperature equalization and hormone transport.

Urinary System

• Included are the kidneys, which filter blood and produce urine.
• The ureters transport urine to the bladder from kidneys.
• The urethra excretes urine out of the body.
• Kidneys produce renin and hormones for regulating functions such as blood pressure.

Respiratory System

• Key structures are nasal passages, lungs, and the trachea.
• The main function is to deliver oxygen to the blood and remove dioxide.
• Gas exchange occurs in the lungs between air and blood.

Lymphatic system

• Sometimes considered part of the immune system.
• System is a network of vessels and ducts that collect and transport lymph to the bloodstream.
• Lymph nodes and the spleen filter blood and lymph, removing pathogens and debris.
• The immune system is aided by the Thymus gland which creates white blood cells.

Digestive System

• Made up of organs including the mouth, esophagus, stomach, and intestines.
• Food passes along this tract.
• Accessory organs, like the liver and pancreas, allow for chemical components to be absorbed.

Reproduction System

• Male system: Production of sperm.
• Female system: Production of egg cells.
• The female system nourishes a developing child.
• Both show high degrees of sexual differentiation.

Immune System

• It protects from pathogens.
• The system has specialized cells and molecules for defense.
• The digestive, cardiovascular, respiratory, endocrine, and nervous systems will be discussed.
• The immune system will be further analyzed under the topic of Disease and Global Health.

Digestion

• Essential for breaking down food for bodily functions.
• Twofold approach: break down & nutrient absorption.
• Mechanical digestion occurs as food breaks apart from the result of motions, and teeth.
• Chemical digestion occurs during breakdown of proteins, fats, carbohydrates.

Chemical Digestion

• It employs digestive enzymes, functioning as catalysts.
• Reactions are all hydrolysis reactions.
• Lipases act on fats, proteases act on proteins, and amylase acts on starch.
• The mouth, stomach, and small intestine partake in chemical processes.

Absorption

• Digested molecules pass through the wall of the small intestine, entering the bloodstream.
• Nutrients in the small intestine are absorbed through diffusion.
• Villi and villi increase the rate of transfer to the bloodstream for energy.

Cardio System

• Transports vital nutrients to cells.
• Includes blood vessels with the heart, and valves regulating flow.

Blood Vessels

• Associated with the heart, lungs, kidneys.
• Arteries carry blood away.
• Veins carry blood back.
• Capillaries supply nutrients and remove waste.

The Heart

• It is a double pump: low pressure to the lungs, high pressure to the body.
• Blood passes through the heart twice per circulation for efficiency.

Deoxygenated Blood

• The right side of the heart collects deoxygenated blood and sends it to the lungs.

Oxygenated Blood

• The left side collects it from the lungs and pumps it to the body.

Heart Structure

The heart has four chambers:

• Right and left atria (receive blood) and push it into the ventricles.
• Right and left ventricles (receive blood from the atria) and push it into arteries.
• Blood flows from a vein, to an atrium, into a ventricle, and then out through an artery.
• The heart has valves that stop blood from flowing backwards.

Double Circulation System

• Right side pumps blood through the pulmonary circuit.
• Left side pumps blood through the circuit to the rest of the body.
• A septum separates the right and left sides.

Pulmonary Circulation

• The blood goes from the heart to the lungs for oxygenation and then back to the heart.
• Deoxygenated blood enters the right atrium via the venae cavae.
• The blood is pumped to the right ventricle.
• Blood moves via the pulmonary valve and into the pulmonary artery from the right Ventricle.
• The artery has sections; right and left to each lung .
• In gas exchange, blood carries dioxide, and oxygen is added.
• A complete circuit occurs when oxygenated blood leaves through the pulmonary veins and enters the left atrium.

Systemic Circulation

• The movement of blood from the heart to the body.
• The blood goes from the heart and provides oxygen and nutrients.
• The deoxygenated blood heads to the heart.
• Blood leaves through the pulmonary veins.
• Then blood goes through mitral valve into the left Ventricle.
• Blood goes up through the aortic valve into the aorta.
• The aorta has sections, as it splits into arteries for the upper body and then supplies the lower zones. Gas exchange, oxygen and glucose are exchanged between blood and cells, and oxygen transfers.
• Capillaries combine into veins, then the blood merges into the venae cava, and which brings it to the right atrium.

Respiratory System - Overview

• Gas exchange involves the movement of gases in and out of cells via a transport system.
• Key surface for gas exchange is in the mammal lungs.
• Ventilation refers to the movement of air in and out of the alveoli.
• Ventilation is important for gas transport.

Alveoli

• Ventilation occurs in the alveoli (air sacs).
• Ventilation of the lungs ensures fresh air enters.
• A concentration gradient will result.
• Gradient allows it to move into the alveoli alongside intercostal muscles.

Gas Exchange

• Occurs in the lungs between alveolar air and capillaries.
• Relies on diffusion.
• Air has a higher concentration than the concentration within the blood.
• The gradient assists gas exchange during cellular respiration.
• Gas transfers primarily through diffusion during ventilation.

Efficient Diffusion

• It can occur through a short diffusion distance.
• It can occur with a large surface area.
• It can occur through good ventilation with air, concentration gradient.
• Good blood supply helps oxygen transport to tissue, removing dioxide.
• The nervous system can alter states of attitude and behavior.
• All vertebrates have a nervous system consisting of: the central, and peripheral nervous systems.

Nerves

• A reflex is an automatic involuntary response.
• The stimuli goes from the sensory receptors, the spinal cord, the brain, then impulses go back to the body.
• Neurons are cells that form a response chain.
• Bundles of fibers from neurons form nerves.
• Impulses travel through the axon.
• The synapse is a site of electric transmission between two neurons.
• A sensory neuron passes information from a receptor to a location such as the brain.
• A motor neuron sends information to an effector (muscle).
• Sensory neurons carry the action to the effector.
• The neuron types are mechanoreceptors, thermoreceptors, sonoreceptors, photoreceptors, & chemoreceptors.

Reflex Arc

• The reflex arc is how the sensory mechanism that controls movement, reflex, and response is maintained as a stimulus.
• Neurons form functional groups.
• Sensory neurons send impulses and a central interneuron will come into contact with the motor neuron.
• The effector is carried to the receptor.
• Thermoreceptors sense the temperature and the impulse signals a nerve action along the chain.
• Chemicals release (neurotransmitters from axon terminal/synapse).
• Released neurotransmitters float in between all surrounding neurons.
• They assist moving of continuous impulses through steps.
• Sensory neurons cause one to think from command of one's body that may signal heat is sensed.
• The cord receives this impulse that relays passing of sensory neurons to motor neurons.
• The brain communicates; motor neurons synapse that results in the contract to remove oneself.

Endocrine System

• It uses hormones to coordinate body systems.
• Key parts are the hypothalamus, Pineal body, Pituitary gland, Thyroid and parathyroid, Thymus, Adrenal gland, Pancreas, Ovary, and Testis.

Hormones

• The hypothalamus secretes hormones that release hormones in the pituitary.
• The Pineal body releases melatonin hormone.
• Pituitary controls the endocrine glands.
• The Thyroid and the parathyroid both affect the body.
• Thymus makes white blood cells.
• The Adrenal controls hormone releases, with aid from the hypothalamus and pituitary.
• As does glucagon and insulin, created in pancreas.
• The Ovary makes estrogen, which causes reproductive responses.
• Testis creates response in men for libido.

Hormones/Neurotransmitters

• 2 types of chemical signalling molecules (messengers).
• A hormone circulates in fluids that produces effects to help the cell.
• Neurotransmitters aid communication between systems (transmitters are proteins).
• Hormones aid development of the immune system and the body temperatures.
• In animals the hormones are sent to certain destinations.
• Hormones could be lipids, molecule material, or proteins.

Tropism

• Phenomenon that is a biological turning movement in a organism (plant).
• Response is dependent on the incoming stimulus that will determine the response.
• The two forms of the process are: positive, or negative.
• The stimulus are: Phototropism, Hydroptropism, and Gravitropism.
• The steps are stimulus detecting, hormone production, and directional growth.

Auxin Hormone

• Regulates growth.
• Occurs due to auxcin equal in the cell
• In order the bend to the light, the hormone moves to cells closely.
• Auxin accumulates in the spaces.
• It diffuses the cells toward the process, then activating certain enzymes.
• Causes elongation.

Immune System

• The system contains substances on the skin, tissue, and body fluids.
• Consists of the innate and adaptive immune system which work close and take on task.
• The innate system defends the body due to quick responses.
• Occurs that virus have the ability to enter into the body.
• It is then up to the system, but limited to not spread infection.
• Functions of that part protects thru the skin mucus membranes.

Adaptive

• The system removes germs, when innate is not strong enough.
• Targets germs that targets a specific immune response.
• It has to identify germs.
• This method allows the system to respond faster, and “remember.”
• The system does not allow illness to affect the body longer, and there are B and T lymphocytes.

White Blood Cells

• Works to protect the body alongside the adaptive and non-specific immune styles.
• Leukocytes assist by aiding the defense against infectious diseases.
• Leukocytes have innate and adaptive components.
• Macrophages engulf certain items in the body to internalize pathogen.
• Eosinophils are one of the components responsible for multicellular parasites.
• Basophils contains histamine released to relieve allergic reactions.
• Main types in the process are T, and B Cells.
• B Cells produce antibiotics.
• T cells are responsible for getting rid of virus and cancer.

Explore the digestive functions and processes of the small intestine. Understand the crucial role of villi and microvilli in nutrient absorption. Learn about enzymes, their substrates, and optimal conditions for digestion.