Physiology Unit Exam (Biology III Exam 4)

Homeostasis

The ability to maintain stable internal conditions even when the outside environment changes.

Receptor, Control Center, and Effector.

Homeostasis involves 3 components, which are?

Maintain a set point

The goal of homeostasis is to?***

Negative feedback

A key mechanism that may increase or decrease in response to the stimuli with a goal of reversing the "direction", may shut down or reduce (sweat to lower temperature, shiver to higher temperature).

Used to "stabilize" and then bring the system back to homeostasis.***

Positive feedback

A key mechanism that increases or cascades a response until a specific endpoint is reached (e.g., labor contractions or clotting).

Used to "amplify" a response until an endpoint (NOT TOWARDS HOMEOSTASIS).***

True

T or F? Homeostatic imbalance leads to disease.

Endotherm

An organism that is internally warmed by a heat-generating metabolic process (circulatory system and vasodilation).

Ectotherm

An animal whose body temperature varies with the temperature of its surroundings. These animals need to find cooler or warmer places to maintain a stable internal temperature.

Pyrogens

Bacteria and viruses that elevate body temperature (fever-producing substances).

1. Leukocytes destroy bacteria and release pyrogens into the blood.

2. Pyrogens signal to the hypothalamus to reset the set point (raising temperature).

Two steps of thermoregulation (governed by the hypothalamus)

Metabolism

All the needed chemical processes that occur in a living organism for survival.

Standard Metabolic Rate

The metabolic rate of a fasting, nonstressed ectotherm at rest at a particular temperature.

Basal Metabolic Rate

The rate at which heat is produced by an individual (endotherms) in a resting state.

Alligator - 60 kcal/day. Humans - 1300-1800kcal/day

Metabolic rate comparison between alligators (ectotherms) and humans (endotherms)

Basal vs Standard Metabolic Rate

Standard metabolic rate applies to ectotherms, requires standardized conditions, and is measured at a specific temperature. Also, the purpose of the process is to serve as a comparable baseline across several different temperatures/species.

Basal metabolic rate is the minimum amount of energy your body needs to survive. It applies to endotherms and requires very specific conditions for measurement. "The true baseline metabolism".

Metabolic rate relation to size

Smaller organisms have a higher surface area-to-volume ratio, causing faster heat loss (which requires a higher Basal Metabolic Rate to maintain body temperature).

Larger animals lose heat more slowly and therefore have a lower metabolic rate per unit mass.

False (typically 2-4 times higher due to activity and other physiological processes)

T or F? Total daily expenditure of energy is about the same as resting energy use.

Kidneys, Metabolism, Fur, Cheek pouches, digging burrows, jumping, bathing, and Na+/K+/ATPase activity.

Specialized adaptations/behaviors that allow kangaroo rats to live in the desert.***

Kangaroo rats produce dry feces and produce highly concentrated urine (reducing evaporative water loss) to conserve water.

Adaptations in kangaroo rat discharge that enable them to live in the desert:***

They obtain water from food metabolism (seeds, as well as vegetation/insects).

How does the metabolism of kangaroo rats allow them to live in the desert?

Relatively high (35 C) due to their soft, dense, silky fur that helps keep them cool.

The heat tolerance of kangaroo rats is?***

Stressed/dehydrated; otherwise, kangaroo rats prefer their normal seed or vegetation diet.

In the kangaroo rat paper, the researchers found that kangaroo rats only preferred insects over their typical diet when?***

Long hind legs and high jump height relative to their size.

What special capabilities do kangaroo rats have to avoid predators?

Digging dry, warm burrows to store seeds. They also bathe in fine sand to keep their fur clean.

What behaviors enable kangaroo rats to live in deserts?

Increases ion gradients in the kidney, leading to highly concentrated urine that helps with water reabsorption.

How does higher Na+/K+ -ATPase activity in kangaroo rats enable them to live in deserts?

Contradictions learned from kangaroo rat research

Burrows are not actually cool/humid, they are hot and dry.

Kangaroo rats do not avoid heat; they can tolerate high temperatures.

Kangaroo rats are not strictly nocturnal (to avoid heat); they are active early at night when it's still very hot.

Kangaroo rats do not survive on seeds/vegetation alone, as they cannot maintain water balance with seeds alone.***

Obtain water from seeds/vegetation (insects if needed) and metabolically conserve water.

How do kangaroo rats obtain water? Preferred diet?***

Hydrated kangaroo rats were vegetarian, but when stressed, they resorted to eating insects.

In kangaroo rat lab studies, what were their preferred diet?***

They attached sensors to rats, which they later retrieved to measure humidity and temperature.

How did the researchers obtain data from the kangaroo rat burrow?***

Kangaroo rats do not avoid heat; they tolerate it pretty well. Their survival also depends on maintaining water balance under extreme conditions.

What were the main conclusions regarding scientists overturning prevailing or accepted views regarding physiology in the kangaroo rat study?

Specialized heat shock response, mitochondrial protection, and muscle + motor function protection.

Key physiological adaptations that allow Saharan ants to survive in >50 C environments?***

Archetypical

adj. being a perfect example of something; classic. THE MODEL.

Prototypical

(adj) A standard or typical example; an original model on which later models are patterned. FIRST OF ITS KIND.

Xeric

Characterized by or adapted to a dry habitat.

Mesic

Pertaining to environmental conditions of medium moisture supply.

Hydric

Permanently or seasonally saturated with water.

Coprophagy

Consumption of feces

Behavioral avoidance

A tendency to withdraw from potential threats.

Propagate

Reproduce, spread, increase.

Torpor

A state of physical or mental inactivity; lethargy. During hot conditions, the body's metabolism slows down.

Hypothermia

Abnormally low body temperature that is often associated with exposure to cold and windy environments.

Anemometer

An instrument used to measure wind speed.***

Hygrometer

An instrument for measuring the humidity of the air or a gas.***

Stable isotope analysis

Analysis of the ratios of stable (nonradioactive) isotopes of elements such as carbon provides information about ancient diets.***

Heat shock response of Saharan ants

Massive upregulation of heat-shock proteins (Hsp70, Hsp60, Hsp90, etc.) that prevent protein denaturation, ensuring cell survival in extreme conditions - this is characteristic of what organisms response to heat?***

Molecular chaperones

A protein that helps other proteins fold or refold from a partially denatured state.

Have specialized chaperone proteins that maintain protein integrity and ATP production under stress.

How do Saharan ants' mitochondria endure the extreme heat present in their habitat?

muscle structure; movement coordination

Heat stable proteins protect ____ and ____ function in Saharan ants, meaning they must run extremely fast on hot sand.***

They briefly forage at the hottest time of the day to avoid predators and move very fast while doing so (they are on a ~10-minute timer; otherwise, they will die).

Behavioral adaptations of Saharan ants that allow them to thrive in their extremely hot environment?***

Circulatory, Respiratory, Muscular, Skeletal, Lymphatic, Endocrine, Nervous, Digestive, Reproductive, Urinary, and Integumentary.

11 systems of the body?

Circulatory (cardiovascular) system

Primary organs of this system are the heart and blood vessels. Primarily responsible for the transportation of oxygen, blood, nutrients, CO2, and waste.

Respiratory system

The primary organs of this system are the lungs and the trachea. Mainly responsible for the gas exchange that occurs within the body.

Muscular system

Primary organs are muscle groups; this system provides movement and heat production.

Skeletal system

Bones plus tendons, ligaments, and cartilage; provides structure, support, make blood cells, and stores minerals.

Lymphatic system

Composed of a network of vessels, ducts, nodes, and the spleen. Provides defense against infection (immunity).

Endocrine system

Composed of eight major glands that secrete hormones (long-term chemical messengers). The regulatory system of your body.

Nervous system

Composed of the brain/spinal cord (CNS) and nerves. Controls the body's systems, senses, and responses.

Digestive system

A body system that consists of the GI tract. Breaks down food into absorbable units that enter the bloodstream for distribution to body cells, and also removes leftover waste.

Reproductive system

Consists of the gonads that are used for producing offspring, making gametes, fertilization, developing the baby, and milk production.

Urinary system

This system is composed of the kidneys, ureters, bladder, and urethra; it is also responsible for removing liquid waste and regulating blood pH.

Skin

The largest organ in the body is the?

Integumentary system

Consists of the skin, mucous membranes, hair, and nails. Functions as a protective covering, contains sensory receptors, and synthesizes Vitamin D. It also uses sweat glands to lower temperature.

Histology

Study of tissues.

Pathology

Study of disease (examines tissues for diagnosis).

basement membrane

Tissues are formed by cells held together by a _____ _____, which is an extracellular matrix structure

Epithelial, Connective, Muscle, and Nervous.

Four basic tissue types***

Epithelial tissue

A major type of body tissue that covers body surfaces and lines cavities. Ex: Skin, Glands, Linings

Squamous

Flat epithelial cells (simple ____ found in alveoli, capillaries, or Bowman's capsule, stratified ____ found in keratinized skin, or non keratinized mouth/esophagus).***

Cuboidal

Cube shaped epithelial cells (simple____ found in kidney tubules, thyroids, and salivary glands, responsible for secretion).

Columnar

Column shaped epithelial cells (simple ___ found in the stomach and small intestine).

Trachea and the upper respiratory tract.

Pseudostratified Ciliated Columnar Epithelium are found where?

simple

When a epithelium is ____, it consists of one layer.***

stratified (fill-in-the-blank)

When a epithelium is ____, it consists of multiple layers.***

Stratified

Epithelial tissue in multiple layers.

Pseudostratified

This type of epithelial tissue appears to have multiple layers, but all cells are in contact with the basement membrane.

Transitional Epithelium

This type of tissue can shift between a cuboidal and columnar state.

Function: stretches readily and permits distension of urinary organ by contained urine

Location: lines the ureters, urinary bladder, and part of the urethra

Connective tissue

A body tissue that provides support for the body and connects all of its parts (includes bones, tendons, ligaments, adipose, and blood).

Dense connective tissue

Connective tissue that consists of three types: dense regular, dense irregular, and elastic.

Adipose connective tissue

Tissue that stores fat (found throughout the body).

Areolar connective tissue

Function: connective tissue that wraps and cushions organs

Location: widely distributed under epithelia of body.

Compact bone

Hard, dense bone (connective) tissue that is beneath the outer membrane of a bone.

Blood

Connective tissue that is made of plasma, erythrocytes (RBCs), leukocytes (WBCs), and platelets.

Muscle tissue

A body tissue that contracts or shortens, making body parts move (e.g., Smooth, Cardiac, and Skeletal).

Smooth muscle

Involuntary muscle is found in the intestines, where it pushes food along the digestive tract. Also found in arteries and veins.

Cardiac muscle

Involuntary muscle tissue found only in the heart.

Skeletal muscle

A muscle that is attached to the bones of the skeleton and provides the force that moves the bones.

Dendrites

What is this (red)?

Nucleus

What is this (orange)?

Axon hillock

What is this (light blue)?

Axon

What is this (two black lines)?

Cell body (soma)

What is this (magenta)?

Glial cells

Cells in the nervous system that support, nourish, and protect neurons (e.g., Schwann cells, oligodendrocytes).

Schwann cell

What is this (light green)?***

Schwann cell function

A type of glial cell that forms insulating myelin sheaths around the axons of neurons in the peripheral nervous system.

Oligodendrocytes

A type of glial cell in the CNS that wraps axons in a myelin sheath.***

Location. Oligodendrocytes - myelinates multiple axons in the CNS, Schwann cells - myelinates one axon in the PNS.

Oligodendrocytes vs Schwann cells?

Myelin sheath

What is this (purple)?

Myelin sheath function

A fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next

Nodes of Ranvier

What is this (Brown)?

Nodes of Ranvier function

Facilitate the rapid conduction of nerve impulses. Gaps in the myelin sheath to which voltage-gated sodium channels are confined.