Animal Form, Function, Nutrition, and Circulation

Comprehensive review flashcards covering animal anatomy and physiology, tissue organization, bioenergetics, thermoregulation, nutrition and digestion, and cardiovascular and respiratory systems.

What is the distinction between anatomy and physiology in biological systems?

Anatomy is the study of the biological form of an organism, whereas physiology is the study of the biological functions that an organism performs.

How does the streamlined body shape of fast swimmers like the tuna, penguin, and seal illustrate evolutionary convergence?

It demonstrates how different, unrelated species independently evolve similar adaptations when facing the same physical constraints and hydrodynamics of moving through an aqueous environment.

Based on the provided diagram of epithelial tissues, what specific type of epithelium is shown in diagram C and what is its typical organ location?

Diagram C shows simple columnar epithelium, which typically lines organs such as the intestine.

What are the three types of protein fibers found in connective tissue, and what is the specific role of each?

Collagenous fibers provide strength and flexibility; elastic fibers stretch and snap back to their original length; and reticular fibers join connective tissue to adjacent tissues.

Which three types of muscle tissue are shown in the human body diagram, and what is a distinguishing feature of each?

Cardiac muscle contains intercalated disks and contracts involuntarily in the heart; smooth muscle lines internal organs for involuntary movement; and skeletal muscle is striated, multinucleated, and responsible for voluntary locomotion.

According to the diagram of a typical neuron, what are the primary structural components through which an impulse travels?

Signals are received by dendrites, integrated in the cell body (which houses the nucleus), propagated along the axon (insulated by myelin sheaths and Schwann's cells with nodes of Ranvier), and transmitted outward via axon terminals.

How do the endocrine and nervous systems differ in signal transmission speed, pathway, and duration of effect?

The endocrine system broadcasts chemical hormones via the blood to receptive cells throughout the body, yielding relatively slow-acting but long-lasting effects. The nervous system transmits rapid electrical impulses along dedicated pathways to specific cells (neurons, muscle cells, or endocrine cells).

What is the operational difference between an environmental regulator and an environmental conformer?

A regulator uses internal control mechanisms to moderate internal change despite environmental fluctuations (e.g., a river otter regulating body temperature), while a conformer allows its internal condition to vary with external changes (e.g., a largemouth bass conforming to ambient temperature).

How does negative feedback maintain homeostatic dynamic equilibrium?

Negative feedback detects fluctuations above or below a set point as a stimulus and triggers a physiological response that reverses the trend, often shutting the system off as end products build up to restore the variable within a narrow range.

How do endotherms and ectotherms differ in their source of heat and energetic expense?

Endotherms generate heat primarily through cellular metabolism, allowing them to remain active over a broader range of temperatures at a high energetic cost. Ectotherms gain heat from external sources, tolerate greater variation in internal temperature, and have much lower metabolic costs.

How does countercurrent heat exchange reduce heat loss in marine mammals and birds?

Arteries carrying warm blood from the core run parallel and adjacent to veins returning cold blood from extremities; heat transfers between opposing fluid flows, trapping heat in the core before it reaches the body surface.

What is the relationship between an animal's body size and its mass-specific metabolic rate?

Metabolic rate per gram of body tissue is inversely related to body size; smaller animals have a much higher mass-specific metabolic rate, requiring higher oxygen delivery rates, breathing rates, and heart rates compared to larger animals.

What is torpor, and how do hibernation and estivation represent specialized forms of it?

Torpor is a physiological state of low activity and decreased metabolism that saves energy. Hibernation is long-term torpor adapted to winter cold and food scarcity, whereas estivation (summer torpor) enables survival during prolonged high temperatures and scarce water supplies.

According to the nutritional diagram, why do vegetarian diets combine grains like corn with legumes like beans?

Corn is deficient in the essential amino acids tryptophan and lysine, while beans lack methionine; combining them provides all essential amino acids in complete, proper proportions.

How many essential amino acids do adult humans require, and which additional essential amino acid is required by infants?

Adult humans require $8$ essential amino acids, whereas infants also require a $9\text{th}$ essential amino acid: histidine.

What did Richard Smithells's inquiry demonstrate regarding maternal vitamin supplementation?

It demonstrated that multivitamin supplementation (specifically providing folic acid) taken at least four weeks prior to conception significantly reduced the occurrence of neural tube defects in pregnancies.

What is the physiological difference between undernourishment and malnourishment?

Undernourishment occurs when a diet consistently supplies too little chemical energy, forcing the body to break down stored carbohydrates, fats, and body proteins for fuel. Malnourishment results from a long-term deficiency of one or more essential nutrients, leading to deformities, disease, or death.

What are the four sequential stages of animal food processing?

1. Ingestion (taking food in)
2. Digestion (breaking food down into soluble molecules)
3. Absorption (uptake of nutrient molecules by cells)
4. Elimination (expelling undigested material from the body).

What are the four main types of animal feeders and an example of each?

Substrate feeders live in or on their food source (leaf miner caterpillar); suspension feeders filter small particles from water (humpback whale); fluid feeders suck nutrient-rich fluid from a living host (mosquito); and bulk feeders ingest relatively large pieces of food (rock python).

What is the difference between intracellular and extracellular digestion?

In intracellular digestion, food particles are engulfed by endocytosis and hydrolyzed inside vacuoles within the cells. In extracellular digestion, food is enzymatically broken down in compartments outside of the animal's cells.

What is the sequence of digestive organs in an earthworm, and what are the roles of the crop, gizzard, and typhlosole?

The pathway is Mouth $\rightarrow$ Pharynx $\rightarrow$ Esophagus $\rightarrow$ Crop (food storage) $\rightarrow$ Gizzard (mechanical digestion) $\rightarrow$ Intestine (chemical digestion, featuring a typhlosole that increases surface area for absorption) $\rightarrow$ Anus.

Which gastric cells secrete hydrochloric acid and pepsinogen, and how is active pepsin produced?

Parietal cells secrete $H^+$ and $Cl^-$ ions separately into the stomach lumen; chief cells secrete inactive pepsinogen, which is cleaved and activated into pepsin by the acidic hydrochloric acid environment.

Why is fat emulsification by bile classified as mechanical rather than chemical digestion?

Bile salts physically break large fat globules into smaller droplets to increase the surface area available for enzymatic digestion by lipases, without hydrolyzing any chemical bonds.

How does the absorption pathway of amino acids and sugars differ from that of fats in the small intestine?

Amino acids and sugars pass directly through the intestinal epithelium into capillaries leading to the hepatic portal vein; fatty acids and glycerol are reassembled into fats, packaged with cholesterol and proteins into chylomicrons, and transported into lymphatic lacteals.

How do the dental adaptations of carnivores, herbivores, and omnivores reflect their diets?

Carnivores have pointed incisors and canines to pierce and tear flesh, and jagged premolars/molars to shear tissue; herbivores have reduced canines and broad, flat molars to grind tough cell walls; omnivores possess unspecialized dentition adapted to cut and grind.

What are the four chambers of a ruminant stomach and their specific digestive functions?

1. Rumen: Microorganisms ferment and break down cellulose into short-chain fatty acids.
2. Reticulum: Compacts regurgitated masses called cud for re-chewing.
3. Omasum: Extracts and reabsorbs water.
4. Abomasum: The 'true stomach,' where the animal's own enzymes and pepsin digest food and passing microbes.

In the illustrated jellyfish (Aurelia), what structural components make up the gastrovascular cavity to circulate nutrients?

Fluid enters through the central mouth and branches outward through spoke-like radial canals to a circular canal running along the outer bell margin, with cilia driving fluid circulation.

What fundamental structural distinction is illustrated between an open circulatory system and a closed circulatory system?

In an open system (e.g., grasshopper), hemolymph is pumped into open sinuses where it directly bathes organs before re-entering pores in the tubular heart. In a closed system (e.g., earthworm), blood is permanently confined inside continuous vessels separate from interstitial fluid.

Based on the diagram of single circulation in fishes, what is the path of blood and how many capillary beds does it encounter per complete circuit?

Blood passes through the $2$-chambered heart (one atrium, one ventricle) once per circuit, flowing from the ventricle to gill capillaries (1st bed, gas exchange), then to systemic capillaries (2nd bed, nutrient/$O_2$ delivery), before returning via veins to the atrium.

How do the heart chambers and circulatory circuits differ between amphibians, reptiles, and mammals/birds as shown in the comparative diagram?

Amphibians have a $3$-chambered heart ($2$ atria, $1$ ventricle) with a pulmocutaneous circuit; reptiles have a $3$-chambered heart with an incomplete septum dividing the ventricle; mammals and birds have a $4$-chambered heart with fully separated ventricles, completely isolating pulmonary and systemic circuits.

What is the complete sequence of mammalian double circulation starting from the right ventricle?

Right ventricle $\rightarrow$ pulmonary arteries $\rightarrow$ lung capillaries $\rightarrow$ pulmonary veins $\rightarrow$ left atrium $\rightarrow$ left ventricle $\rightarrow$ aorta $\rightarrow$ systemic capillaries $\rightarrow$ superior and inferior vena cava $\rightarrow$ right atrium.

According to the cardiac cycle diagram, what events and durations characterize its three sequential phases?

1. Atrial and ventricular diastole ($0.4\,\text{sec}$): blood enters relaxed atria and ventricles through open AV valves;
2. Atrial systole ($0.1\,\text{sec}$): atria contract, forcing remaining blood into ventricles;
3. Ventricular systole ($0.3\,\text{sec}$): ventricles contract, AV valves close, semilunar valves open, and blood is pumped into arteries.

How is cardiac output defined and mathematically calculated?

Cardiac output is the total volume of blood pumped to the body per minute; it is calculated as heart rate ($\text{HR}$) multiplied by stroke volume ($\text{Cardiac output} = \text{HR} \times \text{stroke volume}$).

What creates the classic 'lub-dup' heart sounds during the cardiac cycle?

The 'lub' sound is caused by the recoil of blood against the closing atrioventricular (AV) valves during ventricular systole; the 'dup' sound is caused by the recoil of blood against the closing semilunar valves during ventricular diastole.

What is the chronological pathway of electrical excitation through the mammalian heart conduction system as shown in the diagram?

1. The sinoatrial (SA) node generates an electrical wave in the right atrium;
2. The impulse delays briefly at the atrioventricular (AV) node;
3. The signal travels down bundle branches to the heart apex;
4. Purkinje fibers spread the signal upward through ventricular walls, triggering ventricular contraction.

What proportion of mammalian blood volume is occupied by plasma versus cellular elements, and what makes up plasma?

Plasma occupies about $55\%$ of blood volume and cellular elements occupy about $45\%$. Plasma is roughly $90\%$ water, carrying dissolved inorganic electrolytes (ions) and major plasma proteins such as albumin, fibrinogen, and immunoglobulins.

What structural adaptations optimize mature mammalian erythrocytes for gas exchange?

They are small biconcave disks ($7\text{--}8\,\mu\text{m}$) providing a high surface area to volume ratio, lack nuclei and mitochondria to dedicate space for $\approx 250\text{ million}$ hemoglobin molecules, and produce ATP exclusively via anaerobic metabolism.

What cascade of biochemical reactions converts a temporary platelet plug into a solid fibrin clot?

Damage to vessel endothelium exposes collagen, attracting platelets to form a plug; clotting factors from platelets, damaged cells, and plasma (including calcium and vitamin K) convert prothrombin into active thrombin, which then converts soluble fibrinogen into insoluble fibrin threads.

Based on the stem cell differentiation diagram, what blood cell types originate from the lymphoid versus myeloid lineages?

Lymphoid stem cells give rise to lymphocytes (B cells and T cells); myeloid stem cells differentiate into erythrocytes, platelets, monocytes, neutrophils, eosinophils, and basophils.

How does a fatty plaque develop within an artery in atherosclerosis as shown in the comparison diagram?

Damage or infection roughens the arterial endothelium, triggering inflammation; leukocytes take up lipids and cholesterol, forming an expanding plaque reinforced by fibrous connective tissue that thickens and stiffens the artery wall while narrowing the lumen.

What clinical blood pressure thresholds define adult hypertension?

Hypertension in adults is defined as a systolic blood pressure above $140\,\text{mm Hg}$ or a diastolic blood pressure above $90\,\text{mm Hg}$.

According to the gas exchange diagram, what are the partial pressures of oxygen and carbon dioxide in the alveoli compared to incoming pulmonary blood?

In the alveoli, $P_{O_2} = 100\,\text{mm Hg}$ and $P_{CO_2} = 40\,\text{mm Hg}$. In blood arriving at the lungs, $P_{O_2} = 40\,\text{mm Hg}$ and $P_{CO_2} = 46\,\text{mm Hg}$, driving net diffusion of $O_2$ into the blood and $CO_2$ into the alveoli.

How does countercurrent exchange in fish gill filaments maximize oxygen uptake from water?

Blood flows through gill capillaries in the opposite direction to water passing over the gills; this maintains a partial pressure gradient favoring $O_2$ diffusion from water into blood along the entire length of the capillary.

How do the ventilation mechanics of amphibians differ fundamentally from those of mammals?

Amphibians use positive pressure breathing, lowering the oral cavity floor to draw air in and then raising it with mouth closed to force air into the lungs. Mammals employ negative pressure breathing, contracting the diaphragm and rib muscles to expand the thoracic volume, lowering intra-alveolar pressure and pulling air inward.

What are the definitions and typical adult resting values of tidal volume and vital capacity?

Tidal volume is the amount of air inhaled and exhaled per normal breath (averaging $\approx 500\,\text{mL}$ in resting humans). Vital capacity is the maximum volume during maximal inhalation and exhalation ($3.4\,\text{L}$ in college-age women and $4.8\,\text{L}$ in college-age men).

Why is ventilation in birds considered more efficient than in mammals?

Birds utilize eight or nine air sacs acting as bellows to circulate air unidirectionally through gas-exchanging parabronchi over two cycles of inhalation and exhalation, preventing incoming fresh air from mixing with oxygen-depleted residual air.

How does the medulla oblongata regulate breathing depth and frequency in response to exercise?

Increased metabolic activity raises blood $CO_2$, which reacts with water to form carbonic acid and lowers the $\text{pH}$ of blood and cerebrospinal fluid; the medulla detects this drop in $\text{pH}$ and signals breathing control circuits to increase the rate and depth of ventilation.

What is the Bohr shift shown in the dissociation curve, and how does it assist exercising tissues?

A decrease in $\text{pH}$ (such as from $\text{pH } 7.4$ to $\text{pH } 7.2$) shifts the oxygen-hemoglobin dissociation curve to the right, lowering hemoglobin's affinity for $O_2$ and promoting greater oxygen release in metabolically active tissues.

In what three forms is carbon dioxide transported in vertebrate blood, and in what proportions?

About $7\%$ of $CO_2$ is dissolved directly in blood plasma, about $23\%$ is bound to hemoglobin, and about $70\%$ is transported in plasma in the form of bicarbonate ions ($HCO_3^-$).

Based on the inquiry bar graph comparing the pronghorn to the domestic goat, what physiological enhancements account for the pronghorn's high aerobic capacity?

The pronghorn displays substantially higher relative values across all five physiological indicators: $VO_{2\,\text{max}}$, lung capacity, cardiac output, muscle mass, and mitochondrial volume, enhancing $O_2$ uptake, circulation delivery, and cellular utilization.

What physiological mechanisms enable Weddell seals and elephant seals to perform extended deep dives?

They store extensive $O_2$ reserves bound to large blood volumes and abundant muscle myoglobin, restrict blood flow to skeletal muscles to preserve oxygen for vital organs, and allow working muscles to switch to anaerobic fermentation once myoglobin stores deplete.