Unit 3 Exam

Electrolytes

compounds that dissociate into ions when dissolved in water

Osmoregulation

driven by the total solute concentration

Osmolarity

concentration of all solutes within a solution

Hyperosmotic

solution A’s osmolarity > solution B’s osmolarity

Hyposmotic

solution A’s osmolarity < solution B’s osmolarity

Isosmotic

both solutions’ osmolarity is the same

Osmotic stress

concentration of dissolved substances in a cell or tissue are abnormal

Osmoconformers

vertebrates are in osmotic equilibrium with their environment

Osmoregulators

vertebrates that actively maintain a relatively constant blood osmolarity due the environment’s condition

What type of environment do freshwater animals live in?

Hyposmotic environment

What type of environment do saltwater animals live in?

Hyperosmotic environment

Challenges of freshwater fish

gain water by osmosis and loses electrolytes by diffusion

Adaptations of freshwater fish

drink less water, excrete large amounts of dilute water, actively take ions through gills

Challenges of saltwater animals

lose water by osmosis, gain electrolytes by diffusion

Adaptations of saltwater fish

drink large amounts of seawater, excrete concentrated urine, actively excrete ions through gills

How do waste products impact metabolism?

They can impact osmolarity and water balance

Ex: NH₄⁺ disrupts cellular respiration/other processes, NH₃ raises pH

What type of wastes do animals execrete?

Nitrogenous wastes like NH₃, urea, uric acid (aquatic animals, sharks/mammals, birds/reptiles)

Homeostasis

maintenance of a stable environment despite external changesH

Homeotherms

animals that maintain a constant internal body temperature

Thermoneutral Zone

range of external temperatures in which metabolic rate is minimal and doesn’t change with external termperature

Poikilotherms

allow body temperature to fluctuate with the environment

Behavioral Thermoregulation

can control body temperature by positioning body in sun/shade

Do homeotherms or poikilotherms have a faster metabolic rate?

Homeotherms, which results in higher food needs

Shivering

skeletal muscles contract and energy is converted from ATP → heat

Nonshivering thermogenesis

brown adipose tissue produces heat instead of ATP

Endotherms

heat byproduct of chemical reactions warms the body

Ectotherms

heat comes from the environment

Controlled variable

characteristic being monitored

Sensors

detect current state of variable

Integrator/Control Mechanism

uses information from sensors to determine what response the hypothalamus should do

Effectors

tissues or organs that can change the control variable’s levels

Negative feedback

control mechanism in homeostasis that activates effectors to reduce difference between variable and setpoint

Positive feedback

control mechanism not in homeostasis that amplifies the original change until a specific event occurs

Urinary System’s Function

filter blood, maintain osmoregulation, and eliminate nitrogenous wastes

Kidney

primary filter organ that's composed of nephrons

Cortex

outer region of kidney

Medulla

inner region of kidney

Ureter

long tube that transports urine from kidney → bladder

Bladder

organ that stores urines

Urethra

tube where urine is release and execreted

Renal artery

brings blood containing nitrogenous wastes into kidney

Renal vein

carries clean blood away

Urinary System’s Stages

filtration, reabsorption, secretion, excretion

Filtration in Urinary System

fluid from blood under pressure is filtered; cells and large molecules remain in blood, water/small solutes enter nephron

Bowman’s Capsule’s Function

where filtration stage occurs in the urinary system

Reabsorption in Urinary System

useful ions/molecules are transported from tubular filtrate → body fluids; water follows by osmosis

Secretion in Urinary System

specific ions/molecules are selectively transported from the body’s fluids → tubule

Execretion in Urinary System

wastes and excess water are eliminated as urine

Renal Corpuscle

made up of glomerulus and Bowman’s capsule

Glomerulus

cluster of capillaries that bring blood to the nephron from the renal arteryB

Bowman’s Capsule

region of nephron that surrounds the glomerulus

Proximal Tubule

active transport of Na⁺/K⁺- ATPase creates a concentration gradient where nutrients can be reabsorbed into the cell

Loop of Henle

creates an osmotic gradient

Medula’s Osmolarity

high osmolarity

Cortex’s Osmolarity

low osmolarity

Descending limb

loses water to tissue surrounding to nephrone, passive moment, permeable to water

Thin ascending limb

fluid loses Na⁺ and Cl^-, moves passively along gradient

Thick ascending limb

additional Na⁺ and Cl^- are actively transported out of the nephron

Distal Convoluted Tubule (DCT)

brings in substances through Na^+/K⁺ pump where blood pH is at 7.4 by secreting H⁺ into urine and reabsorbing HCO₃^-

Secretion in DCT

ADH hormone regulates water retention stimulated by increased blood osmolarity and decreased blood volume

Collecting Duct

urine osmolarity is adjusted based on hydration levels

Flow of filtrate

Bowman’s space -→ proximal convoluted tube (PCT) -→ loop of Henle → distal convoluted tubule (DCT) → collecting duct → renal pelvis → ureter → bladder → urethra

Flow of blood

Renal artery → afferent arteriole → glomerulus → efferent arteriole → peritubular capillaries/vasa recta → renal vein

Neurotransmitters

send messages with neurons to relay information, occurs in animals

Hormones

relay information to distant cells to trigger a specific response, which could be peptides/steroids/gases (plants/animals)

Plant hormones

influence plant growth and development as well as responses to the environment

How are plant hormones moved?

Xylem/phloem sap → transported through membrane proteins by simple diffusion

Stimulus Process

stimulus → sensor → signal → response

Response

ligand binds to its receptors and signal transduction

Ligand

chemical signal

Signal transduction

cascade of events that lead to a response

Hydrophobic Hormones

non-polar, diffuse across plasma membrane, enter cell’s cytoplasm

Ex: steriods

Hydrophilic Hormones

large/polar, can’t cross plasma membrane, remain outside target cells