Plant Physiology, Homeostasis, and the Immune System

Vocabulary flashcards covering key concepts from lectures on plant physiology, animal homeostasis, and the immune system.

Root system

Includes all of the plant’s roots and relies on sugar produced by photosynthesis in the shoot system.

Shoot system

Includes the stems, leaves, and (in angiosperms) flowers and relies on water and minerals absorbed by the root system.

Root functions

Anchoring the plant, absorbing minerals and water and storing carbohydrates.

Root hairs

Thin extensions of epidermal cells that increase surface area for absorption of water and minerals.

Mycorrhizal

Fungal symbiosis that increase mineral absorption in most plants.

Leaf

The main photosynthetic organ of most vascular plants, also involved in gas exchange, heat dissipation, and defense.

Veins

The vascular tissue of leaves, parallel in monocots and branching in eudicots.

Dermal tissue system

The outer protective covering in plants, consisting of epidermis and a waxy cuticle to prevent water loss.

Vascular tissue system

Includes xylem (conducts water and minerals) and phloem (transports organic nutrients).

Ground tissue system

Includes cells specialized for photosynthesis, short-distance transport, storage, or support.

Apical meristems

Located at the tips of roots and shoots and at the axillary buds; responsible for primary growth (elongation).

Vascular cambium

Adds thickness in secondary growth by adding layers of vascular tissue (xylem and phloem).

Stomatal pores

Pores in the epidermis of leaves, flanked by guard cells, that regulate gas exchange.

Mesophyll

Ground tissue in a leaf, sandwiched between the upper and lower epidermis; site of photosynthesis.

Endodermis

Regulates passage of substances from the soil into the vascular tissue in roots.

Xylem

Accumulates as wood in secondary growth.

Plant Adaptations

The successful colonization of land by plants due to the evolution of adaptations enabling plants to acquire resources from both above and below ground sources.

Fertilization

Replaces mineral nutrients lost from the soil.

Cations

Positively charged ions in the soil that adhere to negatively charged soil particles, preventing them from leaching out.

Water potential

Combination of solute concentration and pressure that determines the direction of water movement.

Potential

Water’s capacity to perform work, measured in megapascals (MPa).

Solute potential (YS)

The solute potential of a solution, directly proportional to its molarity.

Turgor loss

Wilting due to turgor loss in plants.

Xylem sap

Water and dissolved minerals, transported from roots to leaves by bulk flow.

Cohesion-tension hypothesis

Transpiration and water cohesion pull water along the entire length of the xylem, from shoots to roots.

Transpirational pull

Generated when water vapor in the air spaces of a leaf diffuses down its water potential gradient and evaporates (via stomata).

Abscisic acid (ABA)

Hormone produced in response to water deficiency that causes stomata closure.

Regulating

Using internal mechanisms to control internal change despite external fluctuation.

Conforming

Allowing its internal condition to change in accordance with external changes.

Thermoregulation

Process by which animals maintain an internal temperature within a tolerable range.

Endothermic animals

Generate heat by metabolism (birds and mammals).

Ectothermic animals

Gain heat from external sources (most invertebrates, fishes, amphibians, and nonavian reptiles).

Homeostasis

Maintaining a variable at or near a set point through negative feedback.

Hypothalamus

Brain region that controls thermoregulation in mammals.

Vasodilation

Widening of the diameter of superficial blood vessels, promoting heat loss.

Vasoconstriction

Narrowing of the diameter of superficial blood vessels, reducing heat loss.

Countercurrent exchange

Transfer of heat between fluids flowing in opposite directions, reducing heat loss.

Hormones

Signaling molecules sent out by the endocrine system, affecting single locations or the entire body.

Endocrine Pathway

Pathway where digestive juices in the stomach are extremely acidic and must be neutralized before the remaining steps of digestion take place.

Pituitary gland

A gland located at the base of the hypothalamus in vertebrates, stimulating synthesis and release of hormones from the anterior pituitary.

Feedback Regulation

Loops that links the response back to the original stimulus in an endocrine pathway

Positive feedback

Reinforces a stimulus to increase the response.

Water-Soluble Hormones

Proteins that bind to cell-surface receptors and trigger events leading to a cellular response.

Intracellular Response

Signal transduction with multiple steps.

Osmoregulation

General term for the processes by which animals control solute concentrations in the interstitial fluid and balance water gain and loss.

Osmolarity

The solute concentration of a solution, determining the movement of water across a selectively permeable membrane.

Osmoconformers

Are isoosmotic with their surroundings and do not regulate their osmolarity.

Osmoregulators

Expend energy to control water uptake and loss in a hyperosmotic or hypoosmotic environment.

Ammonia(NH3)

Excretion is most common in aquatic organisms.

Urea

Excretion where vertebrates excrete urea, a conversion product of ammonia, which is much less toxic.

Uric acid

Excretion where insects, land snails, and many reptiles including birds excrete uric acid as a semisolid less toxic paste

Transport epithelia

Layers of epithelial cells specialized for moving solutes in controlled amounts in specific directions involved with waste disposal.

Urine

In most animals, refined a filtrate derived from body fluids

Kidney

Consists of tubules in contact with a network of capillaries in vertebrates.

Filtration

Filtering of body fluids

Reabsorption

Reclaiming valuable solutes

Secretion

Adding nonessential solutes and wastes from the body fluids to the filtrate

Excretion

Releasing processed filtrate containing nitrogenous wastes from the body

Proximal tubule

Where reabsorption of ions, water, and nutrients takes place in kidneys.

Antidiuretic hormone (ADH)

Increase in blood osmolarity above a set point triggers the release.

Renin-Angiotensin-Aldosterone System

A drop in blood pressure near the glomerulus causes to release the enzyme renin which triggers the formation of the peptide angiotensin II.

ATP

An animal’s diet must supply chemical energy for

Organic molecules

An animal’s diet must supply organic building blocks for

amino acids, fatty acids, vitamins and minerals

An animal’s diet must supply essential nutrients

Vitamins

Organic molecules required in the diet in small amounts,divided into fat-soluble and water-soluble.

Minerals

Simple inorganic nutrients required in small amounts.

Malnutrition

Results from the long-term absence from the diet of one or more essential nutrients

Mechanical Digestion

The first stage of food processing includes chewing, increases the surface area of food.

Chemical Digestion

Uses enzymatic hydrolysis to breakdown

Absorption

Uptake of nutrients by body cells

Elimination

The passage of undigested material out of the digestive system

Digestion Compartments

Animals process food in specialized compartments which reduces the risk of an animal digesting its own cells and tissues

Intracellular Digestion

Animals with where food particles are engulfed by phagocytosis and food vacuoles, containing food, fuse with lysosomes containing hydrolytic enzymes

Extracellular Digestion

Animals with breakdown food particles outside of cells in compartments that are continuous with the outside of the animal’s body.

Mammalian Digestive System

The digestive system consists of an alimentary canal and accessory glands that secrete digestive juices through ducts (salivary glands, pancreas, liver, and gallbladder.

Digestion in the Oral Cavity

First stage of digestion that takes place in the oral cavity where teeth chew food into smaller particles that are exposed to salivary amylase delivered by salivary glands through ducts

Gastric Juice

The stomach stores food and secretes

Helicobacter pylori

Gastric ulcers, lesions in the stomach lining, are caused mainly by bacterium.

Small Intestine

Is the longest section of the canal

Duodenum

First portion of the small intestine

Epithelial Lining

Produces several digestive enzymes that complete digestion. Peristalsis moves the chyme and digestive juices along the small intestine

Triglycerides

Fatty acids and monoglycerides diffuse into epithelial cells and are re-formed into

Lymph

Chylomicrons that enter lacteals are carried away by

Liver

Portal vein carries nutrient-rich blood from the capillaries of the villi to the

Cecum

Which aids in the fermentation of plant material.

Success

Mammals is due in part to their dentition which is specialized for different diets is

Basal Metabolic Rate

Is the minimum metabolic rate of a nongrowing endotherm at rest, with an empty stomach, and is not experiencing stress

Standard Metabolic Rate

Is the rate for fasting, nonstressed ectotherm at a particular temperature.

Insulin and Glucagon

Maintain's glucose levels

Over Nourishment

Causes obesity, which results from excessive intake of food energy with the excess stored as fat

Neurons

Signals are electrical or chemical

Ganglia or Brain

Processing of information takes place in simple

Dendrites

Receive signals from other neurons

Axon

Sends signals to other cells

Synapse

Where neurotransmitters pass information from the transmitting neuron to the receiving cell

Neurotranmitters

Where chemical messengers are passed

Glial Cells

Support neurons

Central Nervous System

CNS

Peripheral Nervous System

PNS

Sensory Neurons

Transmit information from eyes and other sensory sensors/stimuli