Lecture 24- Respiration & Excretion Flashcards
How do multicellular aquatic organisms oxygenate their blood?
Gills- countercurrent exchange (diffusion of oxygen from water to blood)
What function does the medulla oblongata contribute to respiration?
Instructs depth/rhythm of breathing
How does the insect respiratory system work?
Tracheal system- gas exchange directly with cells through network ducts
True or False: Most marine invertebrates are osmoregulators.
False; most marine invertebrates are osmoCONFORMERS
The diaphragm contracts during _____.
Inhalation
The basic functional unit of the kidney is the _____.
Nephron
The outer region of the kidney is known as the ____.
Renal cortex
True or False: Respiration is primarily controlled by the somatic nervous system.
False; repiration is primarilly controlled by the AUTONOMIC nervous system
Sequence the four basic processes of excretion.
Filtration → Reabsorption → Secretion → Excretion
What is the glomerulus and what is its function?
Region of clustered capillaries at the start of a nephron which aids in filtration
True or False: The reabsorption and secretion that occur in the kidneys are passive processes.
False; reabsorption and secretion are ACTIVE processes
What are alveoli?
Tiny air sacs in lungs - surrounded by capillaries - site of gas exchange
The glomerulus is located within the _____.
Bowman’s capsule
What is the purpose of deamination?
Excretion of nitrogenous waste
Sequence the pathway of urine.
Kidneys → Ureters → Urinary bladder → Urination (urethra)
The diaphragm relaxes during _____.
Exhalation
What is ammonia converted to in mammalian deamination?
Urea
How is the medulla oblongata stimulated to change respiration patterns?
Cerebrospinal fluid (CSF) pH indicates carbon dioxide concentration + by signals from major blood vessels
The inner region of the kidney is known as the _____.
Renal medulla
Carbon dioxide is converted to _____ in water.
Carbonic acid
Filtration occurs at the glomerulus in the Bowman’s capsule through a process known as _____.
Countercurrent exchange
What is ammonia converted to in reptilian deamination?
Uric acid
True or False: Nephrons are located exclusively in the renal medulla.
False; nephrons span both the renal medulla and renal cortex
Characteristics of Respiratory Structures
Adapted for gas exchange- via air or water
- Thin walls
- Large surface area
- Moist
- Many blood vessels
What are the four main types of respiratory structures?
- Body surfaces
- Gills
- Tracheal system
- Lungs
Respiratory Structure on Body surface
Simplest
Small, low metabolic rate
Must be moist- even if terrestrial
Inefficient- Many also have gills or lungs
Gills
Most common respiration in multicellular aquatic animals
Specialized for gas exchange in water
Folded exchange surfaces
Countercurrent Exchange
Blood and water flow in opposite directions
Blood always meets water with higher O2 content
Maximizes O2 diffusion into blood
Tracheal Systems
In insects
Network ducts, branch throughout body
No circulatory system required for gas exchange
Lungs
Specialized structures for respiration
Primarily in terrestrial vertebrates
Not in direct contact with other parts of body
-> Circulatory system required for gas exchange
Nasal cavity + pharynx
Gas Exchange in Lungs- define lungs and alveoli
Lungs: Paired, spongy, elastic organs within thoracic cavity
Alveoli: Sites of gas exchange within lungs
- Tiny air sacs
- Single cell layer
- Surrounded by capillaries
Breathing Mechanism
Breathing: Mechanical process of moving air in and out of lung
Inhalation: Air in
Exhalation: Air out
Achieved through negative pressure
Inhalation- what does rib cage do, what does diaphragm do, volume, pressure, active or passive
Rib cage expands as rib muscles contract
Diaphragm moves down (contracts)
Volume increase, pressure down
-> Air in
Active process- muscles contract
Exhalation- what does rib cage do, what does diaphragm do, volume, pressure, active or passive
Rib cage gets smaller as rib muscles relax
Diaphragm relaxes (moves up)
Volume decreases, pressure up
-> Air out
Usually passive process
What indicates CO2 levels in body?
pH of blood and cerebrospinal fluid indicates CO2
Higher metabolic rate -> higher CO2-> lower pH
Breathing Control Mechanism
Normal blood pH-> Blood pH falls due to rising levels of CO2 in tissues (such as when exercising)-> Sensors in major blood vessels detect decrease in blood pH-> Medulla detects decrease in pH of cerebrospinal fluid-> Medulla receives signals from major blood vessels-> Signals from medulla to rib muscles and diaphragm increase rate and depth of ventilation-> Blood CO2 level falls and pH rises-> Normal blood pH
Osmoregulation
Regulation of water and solute content in body
What are the two strategies of osmoregulation?
Osmoregulators and osmoconformers
Osmoconformers
Body fluids at equilibrium with surrounding sea water
-> isooosmotic
Only in marine animals
Osmoregulators
Control internal osmolarity independent of external environment
Can live in inhospitable or variable environments
Dehydration + desiccation
Dehydration- from lungs, skin, digestive system, urine
Adaptations to prevent desiccation
- Body covering
- Nocturnal behavior
How do terrestrial vertebrates replace H2O?
- Drinking water
- Eating moist foods
- Metabolic water
Minimize loss by concentrating urine
- Human urine 4x as concentrated as blood
- Desert mammals 20x
What waste products do animals produce?
Water
CO2
Bilirubin
Nitrogenous waste
Lost via respiration or filtration from blood- excretion
Nitrogenous Wastes
Proteins and nucleic acids broken down for E
Converted to fats, carbs
Deamination
Process of removing NH2
-> NH3 (ammonia)- toxic
Types of Nitrogenous Waste
Ammonia- most aquatic animals, including most bony fishes
Urea- Mammals, most amphibians, sharks, some bony fishes
Uric acid- Many reptiles (including birds), insects, land snails
Filtration
Blood contacts transport epithelium: 1+ cell layers, specialized for moving solute in specific directions
Big molecules- cannot pass
Water, small molecules- can pass
Not highly selective
Facilitated by Glomerulus in Bowman’s capsule
Reabsorption
Return of useful substances from filtrate-> body fluid
Done by loop of Henle
Secretion
Active transport of substances from blood-> urine
Important for removal of toxins, excess ions, nonessential solutes
Done by loop of Henle
Excretion
Release of filtrate as urine
Kidney
Principle mammalian excretory organ
Paired bean-shaped structures
2 functions:
Regulate blood composition
Produce urine
What are the two layers of the kidney?
Renal cortex (outer) and renal medulla (inner)
What is the type of nephron we must know?
Cortical nephron
Bowman’s Capsule
Closed end of nephron
Glomerulus
Spherical capillary network in Bowman’s capsule
Exchange between Bowman’s capsule and Glomerulus- filtration
Loop of Henle
Site of reabsorption and secretion
Urine
Continuously produced by kidneys
-> Ureter
-> Urinary bladder (1.5 pints)
-> Exits via urethra
