Respiration and Gas Exchange

Types of Respiration

• Anaerobic respiration does not require oxygen
• Aerobic respiration needs oxygen

External and Internal Respiration

• External respiration transports O2 into and CO2 out of the body, involving the body and external environment
• Internal respiration transports O2 into and CO2 out of cells, involving the body and internal environment

Cellular Respiration and Fick's Law

• Cellular respiration refers to intracellular catabolic reactions that convert stored energy to ATP
• Fick's Law describes the diffusion rate/transport of masses and solutes
• Diffusion depends on concentration gradients and the distance between them

Respiratory Adaptations and Gas Exchange

• Adaptations exist to counter diffusion of gases across respiratory membranes/organs
• Breathing movements are part of ventilation
• Gases diffuse across the respiratory epithelia and capillary walls
• The circulatory system facilitates bulk transport of gases

Respiratory Mediums

• Higher altitude reduces the pressure of oxygen
• Water is more viscous and dense with limited oxygen
• Increased temperature reduces oxygen solubility in water
• Oxygen has less solubility in water

Respiratory System Diversity

• "Water Breathers" are water-breathing animals, possess invaginations of the body called gills
• Cilia beating creates a water current for gill ventilation as water moves over them
• Tracheal systems are used for gas exchange (insects)
• Birds use air sacs and lungs for respiration
• Mammals use mammalian lungs

Fish Gills and Ventilation

• Fish gills use a counter-current gas exchange
• Gills are multifunctional body organs
• Fish have a ventilation system
• Fish have external and internal gills
• External gills extend outside the body
• Internal gills are located within the body
• Fish gills are protected by the body

Fish Gill Water Flow

• Water currents are directed over the gills
• Countercurrent flow in fish gills has blood and water moving in opposite directions
• Blood leaving the capillaries has the same oxygen content as fully oxygenated water entering the gills
• Countercurrent flow allows diffusion because equilibrium is not met, and a concentration gradient exists ensuring maximum oxygen extraction

Avian Respiratory System

• The avian respiratory system uses air sacs and lungs for cross-current gas exchange
• The first inhalation directs most oxygen to the posterior air sacs
• During exhalation, both anterior and posterior air sacs contract
• With the next inhalation, air from the lung flows into the anterior air sac
• The second exhalation expels air from anterior sacs through the trachea
• Blood flows concurrently, with small amounts contacting air

High Altitude Bird Adaptations

• High-altitude flying birds have respiratory adaptations
• These birds have larger lungs and high capillary density in flight muscles

Human Lung Structure

• Human lungs are mammalian lungs using tidal ventilation
• Mammalian lungs have two branching airways
• The trachea divides into two primary bronchi
• Primary bronchi branch and re-branch into bronchioles
• Bronchioles branch into alveoli, which are tiny outpocketings
• Lungs are surrounded by a pleural sac, a fluid-filled sac

Lung Volumes

• Total Lung Capacity (TLC) represents the max air amount capable of being held in the lungs
• Tidal Volume (TV) is the air volume entering and exiting during a single breath
• Functional Residual Capacity (FRC) indicates the air amount left in the lung after exhalation
• Residual Volume (RV) is the consistent air amount in the lungs, the minimum required volume to prevent lung collapse
• Vital Capacity (VC) is the max air amount that can be expelled during a breath following max inhalation (deepest exhalation)

Ventilation and Control

• Tidal ventilation involves fresh air mixing with stale air from a previous breath
• Oxygen's partial pressure decreases as a result
• Peripheral chemoreceptors monitor carbon dioxide pressures and pH for neural breathing control
• The response is to monitor oxygen's pressure

Regulating Ventilation

• Chemoreceptors and mechanoreceptors detect carbon dioxide, pH, and oxygen
• The pons and medulla act as central controllers
• Respiratory muscles serve as effectors

Oxygen and Carbon Dioxide Transport

• Oxygen is carried in the blood by RBCs (98%) and plasma (2%)
• Hemoglobin in RBCs carriers oxygen due to its low solubility in plasma water, needing a carried protein to transport oxygen to tissues
• Hemoglobin is an iron containing oxygen transport metalloprotein found in almost all vertebrate red blood cells
• RBCs are 96% hemoglobin
• Hemoglobin binds up to 4 oxygen molecule
• The oxygen and hemoglobin relationship has a sigmoidal curve
• Binding of oxygen in one site increases the affinity of other oxygenbinding sites

Affects on Hemoglobin

• Hemoglobin's affinity for oxygen is affected by temperature, pH, and CO2

Gas exchange process

• Oxygen diffuses from blood to interstitial fluid to body cells
• 10% of carbon dioxide dissolves in plasma

Carbon Dioxide and Carbonic Anhydrase

• 70% of carbon dioxide is converted into hydrogen and bicarbonate ions
• 20% of carbon dioxide combines with hemoglobin
• Carbonic anhydrase is a metalloenzyme with zinc that catalyzes the interconversion of carbon dioxide and water into bicarbonate and hydrogen ions
• Carbonic anhydrase transports carbon dioxide out of tissues and maintains acid-base balance in blood and tissues
• Carbon dioxide is largely transported as bicarbonate ions in plasma

Cardiovascular Functions

• Homeostasis and metabolism
• Blood clotting factors
• Transport of chemical messengers, hormones
• Antibodies
• Heat movement

Diversity of Circulatory Systems

• Animals don't all require a dedicated circulatory system; some are more complex than others
• Aquatic animals circulate external fluid through an open body cavity
• Insects circulate internal fluid through an open body cavity
• Fish circulate internal fluid though a closed body cavity
• Mammals circulate internal fluid through a closed circulatory system with a double circuit

Open vs. Closed Circulatory Systems

• An open circulatory system has a limited ability to alter blood flow direction/velocity and doesn't supply efficient oxygen flow
• Open systems show distinction between haemolymph and interstitial fluid
• Insect circulatory systems aren't involved in oxygen transport
• A closed circulatory system keeps blood separated from the interstitial fluid

Vertebrate Circulatory Systems

• Systems evolved from single to double circuits, dividing heart chambers
• Single circulation requires a 2-chambered heart (fish is single circuit)
• Parallel circulation utilizes a 3-chambered heart (Amphibians and most reptiles are parallel circuits, partially divided)
• Double circulation utilizes a 4-chambered heart

Circulation

• Blood is oxygenated prior to entering the body
• Birds and Mammals have a completely divided double circuit
• A double circuit uses 2 pumps, pulmonary and systemic, to support cellular respiration

Human Heart

• The human heart structure has 4 chambers being a pump with 2 atria at the top and 2 ventricles at the bottom
• Atrioventricular (AV) valves are located between atria and ventricles
• Semilunar (SL) valves are located between ventricles and pulmonary arteries
• A double circuit utilizes 2 separate pulmonary and systemic circuits

Function of Valves

• Valves open and close due to pressure to prevent backflow

Heart Features

• The heart's muscular thickness is larger in the left ventricle for stronger contraction to propel blood further
• The cardiac cycle involves cardiac muscles (myocardium) and cardiac electrical conduction pathways
• The heart uses high coordination of atria then ventricles with alternating periods of diastole/relaxation and systole/contraction
• Cardiac cycles use a systole-diastole sequence

Blood Pressure and Conduction

• Systolic pressure is the ventricle contraction pressure, pushing blood into arteries at peak pressure
• Diastolic pressure occurs between contractions
• Blood pressure in arteries drops to minimum pressure
• Cardiac conduction uses rhythmical electrical activity

Electrical Heart Activity

• Cardiac muscle fibres (myocardium) have electrical activity from specialized cardiac muscle fibres, auto-rhythmic fibres
• Auto-rhythmic fibres don't need a stimulus to trigger and transmit electric signals through the heart
• Spontaneous fibres are located in the sinoatrial (SA) and atrioventricular (AV) nodes

Myocardium Properties

• The myocardium is striated, with cell-to-cell connections that allow APs to spread
• Tetanic contractions don't occur in the cardiac cycle
• Bradycardia is a heartbeat slower than normal
• Tachycardia is a heartbeat higher than normal
• Arrhythmia is an abnormal heartbeat

Heart Regulation

• The autonomic regulation of the cardiovascular system regulates heart rate via the medulla
• Chemical and blood pressure changes are monitored by chemoreceptors and baroreceptors

Blood Composition

• Blood is a cellular component of important plasma ingredients
• Plasma is 55% of blood volume containing water, proteins, ions, sugars, lipids, and hormones
• Leukocytes, platelets, and erythrocytes make up 45% of the blood volume

Blood Vessels

• Arteries carry blood away from the heart under pressure
• Arterioles deliver blood to capillaries
• Capillaries exchange material with interstitial fluid with a narrow, single-cell layering
• Venules collect blood from capillaries

Arteries vs Veins

• Arteries have thicker walls that contain smooth muscle fibers around the lumen to contract and relax to regulate blood flow compared to veins

Lymphatic System

• The lymphatic system is a key component and the first line of defense of the immune system
• The Lymphatic system maintains fluid balance by collecting excess interstitial fluid and maintaining blood volume and homeostasis
• Key in fat absorption and defense

Digestion & absoprtion

• Nutrients: carbohydrates, fats, proteins composed of monosaccharides, disaccharides and polysaccharides
• Proteins: amino acids held together by peptide bonds.
• Fats: composed of triglycerides, diglycerides, and monoglycerides along with vitamins and minerals
• Metabolism: requires Essential amino and fatty acids
• Nutrients are classified as Essential vs. non-essential and Macro- nutrients (required in large amounts) vs micro- nutrients (required in small amounts)
• Essential nutrients: Animals cannot synthesize themselves and must be acquired from food (lysine, histidine, tryptophan, phenylalanine, threonine, valine, methionine, leucine and isoleucine)
• Essential fatty acids: Linoleic acid (omega-6), linolenic acid (omega-3)

Digestion Types

• Intracellular digestion occurs within the cell with food particles taken in by endocytosis
• Extracellular digestion occurs outside of the cell in a tube enclosed in the body but outside body cells (digestive tract)

Feeder Types

• Fluid feeders ingest liquids containing organic molecules
• Suspension feeders eat small particles of organic matter suspended in fluids through filtration
• Deposit feeders ingest small organic particles from solid matter where feeders live
• Bulk feeders consume large pieces of organisms
• Key differences in GIT, herbivores vs. carnivores and monogastric vs. ruminant
• Omnivores consumes both animal and plant material

Digestion:

• Carnivores have greatly enlarged stomachs with increased secretions, smaller cecums, and shorter gut lengths to digest animal products
• Herbivores have long digestive tracts due to time required to absorb nutrients to digest plant product
• Monogastrics possess a simple single-chambered stomach, an extra muscle layer, and gastric glands secreting gastric juices
• Ruminants have a four-chambered complex stomach consisting of the rumen, reticulum, omasum, and abomasum
• Rumen, reticulum, Omasum, Abomasum function by fermenting food prior to digestion through microbial actions

GI Tract and Swallowing

• Mechanical processing
• Secretion of enzymes and other digestive aids
• Enzymatic hydrolysis
• Absorption
• Elimination
• Swallowing is an involuntary reflex that is regulated by the autonomic nervous system
• Swallowing involves both voluntary and involuntary phases while breathing stops temporarily to prevent food from entering the trachea
• Peristalsis uses involuntary contraction and relaxation of GI tract muscles for peristaltic waves throughout the GI tract

Digestive Parts

• The stomach, small, and large intestine functions differ
• The stomach mixes food with stomach acid and enzymes breaking it down into smaller pieces (chyme)
• The stomach secretes gastric juice, pepsin, intrinsic factor, and gastric lipase
• The small intestine requires an alkaline environment for chemical processes
• Digestion and nutrient absorption complete in the small intestine

Lower Digestive and other Organ functions

• Large intestines has a cecum, appendix, colon, and rectum that secretes mucus and bicarbonate ions
• The large intestine houses symbiotic microbes
• Liver & Pancreas provide accessory digestive functions
• The Duodenum receives digestive juices from the pancreas and liver
• The pancreas produces pancreatic juice containing digestive enzymes and bicarbonate ions
• The liver secretes liver secretions that emulsify fats
• The gallbladder stores bile eventually secreted in the duodenum

More on Enzymes

• Various types, spatial localization of digestive enzymes exists within the G.I.T.
• Most nutrients are broken down by enzymes from various organs in the GI tract.
• Mouth: salivary amylase, lingual lipase.
• Stomach: pepsin, gastric lipase.
• Small intestine: pancreatic amylase, trypsin, chymotrypsin, carboxypeptidase, lipase, pancreatic nucleases.
• Epithelial cells of small intestine: Disaccharidase, Amino peptidase, dipeptidase, Nucleotidases, nucleosidases, phosphatases.

Chemical Digestion and Absorption

• Chemical digestion and absorption of proteins, fats, and carbohydrates

Diffusion

• Lipophilic molecules do not need a carrier
• They use simple diffusion

Chylomicrons and Alternative pathways

• Chylomicrons can’t enter blood capillaries because they are too large and require an alternative blood pathway

Anabolism vs Catabolism

• Anabolism builds complex molecules from simple ones
• Catabolism breaks down complex molecules into simple ones
• Metabolic rate influences body mass consisting of body processes that use or produce energy

Metabolic Properties

• Metabolism occurs at multiple scales
• Metabolic rate describes at what rate body energy is used
• Body metabolism adjusts to meet specific needs
• Body metabolism is adjusted to meet specific needs, body metabolism is very dynamic

Energy Use

• An organisms body metabolism is regulated by the CNS and various hormones in mammals
• Altered oxygen consumption
• Altered carbon dioxide production
• Altered heat production in endotherms

Endocrine Regulations

• Autocrine - act on same cells that release it
• Paracrine - act on nearby different cells than those that release it
• Endocrine - secretion of material into extracellular spaces or blood vessels
• Neuroendocrine - manages the communication between the nervous system and the endocrine system

Hormones

• Major hormones properties, synthesis, storage, signalling & metabolism
• Amines: small water-soluble
• Proteins: water-soluble
• Steroids: derived from cholesterol, mostly lipid soluble

Non steroid hormones.

• Bind to plasma membrane receptors
• derived forms amino acids

Steroid hormones

• Bind to intracellular receptors
• Derived from cholesterol
• Slower pace from non-steroid hormones

Hormones Regulation

• Altering rate of homrone synthesis and secretion
• Removal or filtration mechanisms
• Conversion of inactive forms to active forms of target tissue
• Homeostatic feedback loops

Lipids

• Steroids are lipid soluble which allows crossing cell membranes
• Non steriods are water soluble and must bind to receptors on cell surfaces allowing them to pass through membranes

Insect Development

• Absence of Juvenile hormone allows for metamorphosis to be completed
• Ecdysones steroidhormone found in insects that signals molting
• PTTH (Prothoracicotropic hormone) is secreated by the brain to work on prothoracic gland
• Absence of a hormone can be an important regulator
• Brain or nervous system often regulates hormone release

Human Organ System

• Hypothalamus: master endocrine gland that produces and secrcretes hormone
• Pineal gland: secretes melatonin
• Pituitary gland: anterior - secretes ACTH, TSH, FSH ans LH
• Pituitary gland: posterior - Stores and releases ADH and oxytocin
• Parathyroid glands: secretes parathyroid hormone
• Thyroid gland: secrets thyroxine, triiodothyronine, and calcitonin
• Adrenal cortex: secretes cortisol and aldosterone
• Adrenal medulla: secretes epinephrine and norepinephrine
• Islets of Langerhans: secretes insulin and glucagon
• Ovaries - secretes estrogen and progestins
• Tests- secretes androgens

Characteristics of different body's organ and control system

• Vertebrate endocrine System: More than a dozen of glands, some have only endocrine fuctions and some have more than just endocrine functions
• only adrenal glands and sex organs produce steroid hormones
• Hypothalamus- its control center of endocrine system action through the pituitary gland
• Negative feedback control or different endocrine axis
• Posterior pituitary extension of the hypothalamus nervous tisse, store and secretes the hypothalamus hormone
• Anterior Pituitary: Glandular tissue. Produces and secretes its own hormone

Role of growth hormone by thyroid Gland

• Stimulate muscle and tissue growth throughout the body
• Promotes development and enlargement of all body part
• Overproduction: hypersecretion or growth hormone

Multifunctional Thyroid Gland for body function and Homeostasis

• Produces T4 and T3 with Iodine presence regulates blood pressure, heart rate, muscle tone, body temperature, digestion and reproduction
• Important cellular regulators of metabolism in endotherm for maintaining metabolic rate which can stimulate energy production in mitochondria
• Acute Response: Adrenaline rush, almost immediately, activated Sympathetic division and prepares body for immediate survival and adrenal gland secretes two hormones, epinephrine and norepinephrine
• Delayed by a few minutes, activated with hypothalamic-pitutary axis which makes to prepare them for long term stress
• Regualtes digestion and metabloism

Blood Calcium

• Calcitonin regulates blood-calcium homeostasis by bring the calcium back to the set-point
• Primarily invertebrates
• No genetic diversity,babies are genetically identical to parents and sibling.

Asexual Modes

• New individual rises from an outgrowth of an older one budding
• One individuals separates into two or more individuals of about equal size fission
• Individual breaks into small pieces and each piece can form a new individual :Fragmentation/regeneration
• Development of an individual forms an unfertilized egg :parthenogensis

Sexual and Reproduction

• Primarily vertebrates, diploid produces haploid sex cells ,mixing of genetic material provides genetic diversity,
• Switching gametes with another individual :hermaphrodism different reproductive strategies
• Advantages and disadvantages -environmental factors, resource availability, temperature, stressors.etc

Diverse reproduction: Genetic variability

• Allows for favourable genes to be produced and for adaptations to occur

Gametogenesis and roles

• Cellular process in which gametes are produced, human males and females with endocrine system and control
• Ovaries produced eggs through oogenesis ( I ovum) Femals; test produces sperm through spermatogenesis (4 sperm) Males FSH stimulates one follice to develop, estradiol stimulates the growth and development of oocyte, LM triggers ovulation.

Embryo properties

• Progesterone released from corpus leteum prepares the uterus to recieves the embyo
• Semi-solid gelatinous layer zona pillucida and a glycoprotein layer with vitelline coat

Sperm

• Small mobile cell, made op of head mitochondrial and tails contains nulceus and acrosomes, acrosome
• Combine two hapliod gamete to form as diploid zygotes sperm contact jelly layer of egg
• Sprosmes release enzymes to break down,egg membrane vitelline receptors in sperm bind two head membrane has specie specific. Placenta Membrane fuse; sperm: cytoplasm to enter into egg cytoplasm. fuse together to form into zyote which equals to hapliod diploid different stages In animal develop

Ferts

• Less energy and intrenal more reproduction different stages In animals development
• Cleavage morula, solid of solid with cell division and cell migration, no increase insize or mass just change mount of cells morula made and animal vegetal pole
• Animal pile:where,nucleus is located, vegetal poles: is less active and contain ver liteel cutipsum
• Gratsulation:grastual layers: continued division and migration embryonic cells forms ecto endo and meso
• Invagination at blastepore forms archenteron certin surface bastomare which Migrate inside and and create smail opening

Four mation type

• Furmation or brain and cns local changes in cell shap,szie and number
• cells migration Apoptosis and from from membrae break down
• Programmers cell death