Unifying Concepts of Animal Structure and Function

Question 1

Anatomy

Answer 1

Study of the structure of an organism´s parts.

Question 2

Physiology

Answer 2

Study of the function of an organisms parts.

Question 3

Tissue

Answer 3

Tissue is a group of similar cells that work together to perform a specific function in an organism.

Question 4

Epithelial tissue

Answer 4

Epithelial tissue is a type of tissue that forms the covering or lining of all internal and external body surfaces. It serves as a protective barrier, controls permeability, and functions in secretion and absorption. Epithelial tissue is classified based on the number of cell layers (simple or stratified) and the shape of the cells (squamous, cuboidal, or columnar). It can be found in structures such as the skin, the lining of the digestive tract, and the walls of various organs and glands.

Question 5

Connective tissue

Answer 5

Connective tissue is a type of tissue that provides support, binds together, and protects tissues and organs of the body. It is characterized by an abundance of extracellular matrix, which can include fibers (such as collagen and elastin), ground substance, and various cell types (such as fibroblasts, macrophages, and adipocytes).
There are several types of connective tissue, including:

Loose connective tissue: Supports and binds other tissues, with a loose arrangement of fibers. Examples include areolar tissue and adipose tissue.

Dense connective tissue: Provides strength and support with densely packed fibers. Examples include tendons and ligaments.

Cartilage: Provides flexible support and reduces friction between bones. It includes hyaline cartilage, elastic cartilage, and fibrocartilage.

Bone: Provides rigid support and protection, stores minerals, and houses bone marrow.

Blood: Transports nutrients, gases, and wastes throughout the body.

Fibrous Connective Tissue: This type of connective tissue is characterized by densely packed fibers that provide strength and support. It includes:

Dense Regular Connective Tissue: Found in tendons and ligaments, with parallel collagen fibers for strength in one direction.
Dense Irregular Connective Tissue: Found in the dermis of the skin and organ capsules, with irregularly arranged fibers for strength in multiple directions.

Adipose Tissue: Specialized connective tissue that stores fat. It provides energy reserves, insulation, and cushioning for organs. There are two types:

White Adipose Tissue: The most common, stores energy and insulates the body.
Brown Adipose Tissue: Rich in mitochondria, helps in heat production, especially in infants.

Question 6

Muscle tissue

Answer 6

Muscle tissue is a type of tissue that is specialized for contraction and movement. It is composed of cells called muscle fibers, which contain actin and myosin filaments that slide past each other to produce movement. There are three main types of muscle tissue:

Skeletal Muscle:
Structure: Long, cylindrical, multinucleated cells with a striated (striped) appearance.
Function: Voluntary movements of the body, such as walking and lifting.
Location: Attached to bones by tendons.

Cardiac Muscle:
Structure: Branched, striated cells with a single central nucleus; connected by intercalated discs that allow synchronized contraction.
Function: Involuntary contraction to pump blood throughout the body.
Location: Walls of the heart.

Smooth Muscle:
Structure: Spindle-shaped, non-striated cells with a single central nucleus.
Function: Involuntary movements, such as controlling the diameter of blood vessels and moving food through the digestive tract.
Location: Walls of hollow organs, such as the intestines, blood vessels, and bladder.

Question 7

Nervous tissue

Answer 7

Nervous tissue is a specialized tissue that is involved in receiving, transmitting, and processing information through electrical and chemical signals. It is the primary component of the nervous system, which includes the brain, spinal cord, and peripheral nerves.

Question 8

Neurons

Answer 8

Neurons are the functional units of nervous tissue. They have a cell body (soma), dendrites (branching processes that receive signals), and an axon (a long projection that transmits signals to other neurons, muscles, or glands).

Function: Neurons are responsible for sensing stimuli, processing information, and transmitting signals.

Question 9

Organ

Answer 9

Collection of tissues that structurally form a functional unit specialized to perform a particular function.

Question 10

Organ systems

Answer 10

Groups of organs that work together to perform specific functions in the body, like the heart and blood vessels in the cardiovascular system, or the brain and nerves in the nervous system.

Question 11

Open system

Answer 11

A system that interacts with its environment, allowing for the exchange of matter and energy across its boundaries. This exchange enables the system to adjust and adapt to external influences.

Closed systems do not exchange matter with their surroundings (though they may exchange energy).

Question 12

Homestasis

Answer 12

Homeostasis refers to the body’s ability to maintain a stable internal environment despite external fluctuations.
This regulation involves various physiological processes that keep essential variables such as temperature, pH, blood sugar levels, and fluid balance within a narrow range.

Question 13

Interstitial fluid

Answer 13

Interstitial fluid is the fluid found in the spaces between cells in tissues. It fills the gaps and surrounds cells, providing them with nutrients and oxygen while also removing waste products. This fluid is crucial for maintaining the proper environment for cellular function and plays a vital role in facilitating the exchange of substances between blood vessels and cells.

Question 14

Negative feedback

Answer 14

Regulatory mechanism where a change in a physiological variable triggers a response that counteracts the initial change, thereby maintaining the stability of the internal environment of an organism.

Stimulus: A change occurs in the internal environment (e.g., an increase in body temperature).
Sensor: This change is detected by sensors (e.g., nerve cells or endocrine cells).

Control Center: The sensor sends the information to a control center (often the brain or endocrine glands), which processes the information.

Effector: The control center activates effectors (muscles, organs, or glands) that produce a response to counteract the change.

Response: The effectors’ actions bring the physiological variable back toward its set point, reducing the initial stimulus.

Question 15

Positive feedback

Answer 15

Positive feedback is a regulatory mechanism in which a change in a physiological variable triggers responses that amplify the initial change, leading to an even greater deviation from the original state.

Stimulus: A change occurs in the internal environment (e.g., the onset of labor contractions).

Sensor: This change is detected by sensors (e.g., nerve cells or endocrine cells).

Control Center: The sensor sends the information to a control center (often the brain or endocrine glands), which processes the information.

Effector: The control center activates effectors (muscles, organs, or glands) that produce a response to enhance the change.

Response: The effectors’ actions intensify the initial change, leading to an amplified response.

Question 16

Thermoregulation

Answer 16

Thermoregulation is the process by which an organism maintains its internal body temperature within an optimal range despite external temperature changes.

Question 17

Endotherms

Answer 17

The ability to maintain a body temperature substantially warmer than the surrounding. (ex. metabolism).

Question 18

Ectoherms

Answer 18

Organisms that rely primarily on external environmental sources to regulate their body temperature. They do not generate much internal heat through metabolism and instead depend on behavioral adaptations to manage their thermal state.

Question 19

Fever

Answer 19

A fever is a temporary increase in body temperature, often due to an infection, as part of the body’s immune response.

Question 20

Osmoregulation

Answer 20

Osmoregulation is the process by which organisms regulate the balance of water and electrolytes (salts) in their bodies to maintain stable internal conditions. This involves mechanisms to control water intake and excretion, as well as the concentration of ions, ensuring proper cell function and overall homeostasis.

Question 21

Homeostasis in the urinary system

Answer 21

Maintaining the body’s internal balance by regulating the composition and volume of bodily fluids, primarily through the production and excretion of urine. Takes also care of the excretion of wastes.

Filtrate: Imagine your blood is like a river flowing through your body. In the kidneys, tiny filters called glomeruli catch the waste and extra stuff from this river, forming a fluid called filtrate.

Tubules: Picture these tubules as tiny tunnels where the cleaning process happens. As the filtrate moves through these tubules, the good stuff your body needs, like water and important nutrients, gets absorbed back into the bloodstream.

Waste Removal: The leftover stuff, like excess salts and waste products, stays in the tubules and becomes urine. The urine then travels down tubes called ureters to your bladder, where it’s stored until you’re ready to pee it out.

Balancing Act: Throughout this process, the urinary system keeps a close eye on things, making sure the right balance of water, salts, and other substances is maintained in your body. This helps keep you healthy and your internal environment just right, like a well-maintained machine!

Question 22

Nephron

Answer 22

Functional unit of the kidney responsible for filtering blood, removing waste products, and regulating the balance of water and electrolytes in the body through urine formation. It consists of a glomerulus, a renal tubule, and associated blood vessels.

Question 23

Urine

Answer 23

Urine is a waste fluid produced by the kidneys through the filtration of blood. It contains water, electrolytes, and waste products such as urea.

Question 24

Urinary bladder

Answer 24

Urine is stored in the urinary bladder and the urine is later expelled from the urinary bladder via the urethra (tube).

Question 25

Major functions of a nephron

Answer 25

The major functions of a nephron include filtration, reabsorption, secretion, and excretion:

Filtration: The nephron filters waste products, excess ions, and water from the blood at the glomerulus, forming a fluid called filtrate.

Reabsorption: Essential substances such as water, electrolytes (sodium, potassium, calcium), and nutrients (glucose, amino acids) are reabsorbed from the filtrate back into the bloodstream to maintain proper balance.

Secretion: The nephron secretes waste products, drugs, and excess ions (e.g., hydrogen ions, potassium ions) from the bloodstream into the filtrate for excretion from the body.

Excretion: The remaining filtrate, now urine, containing waste products and excess substances not reabsorbed, is excreted from the body through the ureters, bladder, and urethra.

Question 26

Ureter

Answer 26

The ureter is a muscular tube that carries urine from the kidneys to the urinary bladder.

Question 27

ADH (Antidiuretic Hormone)

Answer 27

Hormone produced by the hypothalamus and released by the pituitary gland. ADH plays a key role in regulating the body’s water balance by controlling the amount of water reabsorbed by the kidneys. When ADH levels are high, the kidneys reabsorb more water, leading to concentrated urine and conservation of water in the body.

When ADH levels are low, less water is reabsorbed, resulting in dilute urine and increased water loss through urination. ADH secretion is influenced by factors such as blood osmolality, blood volume, and blood pressure, helping to maintain proper hydration levels in the body.