Lecture 12: Structure & Function of Animals

What is the hierarchical organization of animal bodies?

cell —> tissue —> organ —> organ system —> organisms

What is a cell?

organelles + cytosol enclosed within the plasma membrane

What is tissue?

a group of cells with similar structure and/or function

What is an organ?

multiple tissues that come together to form an organ

What is an organ system?

multiple organs working together towards a common function

What is an organisms?

All the organs system functioning together

What are the four major tissue?

epithelia tissue, muscle tissue, connective tissue, nervous tissue

What does epithelial tissue function in?

protection, secretions, and absorption

What does connective tissue function in?

connecting and supporting body structures

What does muscle tissue function in?

functions in moving the body and substances within the body

What under and not under conscious control for muscle tissue?

Skeletal muscle is under conscious control whereas smooth and cardiac muscle is not under conscious control

What does nervous tissue function in?

is transmitting information throughout the body in the form of electrical signals

What is the eleven organ systems?

Circulatory, Respiratory, Excretory, Digestive, Integumentary, Nervous, Immune, Skeletal, Endocrine, Muscular, and Reproductive Systems

What is the function of the Circulatory System?

transports gases, nutrients, and other substance throughout the body

What is the function of the Respiratory System?

gas exchange with the external enviornment

What is the function of the Excretory System?

maintains a constant solute concentration in body fluids (osmoregulation) and removes nitrogenous waste

What is the function of the Digestive System?

digestion of food, absorption of nutrients, remove undigested wastes

What is the function of the Integumentary System?

protection from the external environment, detects stimuli, and conducts thermoregulations

What is the function of the Nervous System?

transmit information throughout the body via electrical signals; processes information, senses and responds to stimuli, and controls & coordinates organs and physiological processes

What is the function of the Immune System?

protects & defends the body against foreign substances and pathogens

What is the function of the Skeletal System?

support structure for the body, protects internal organs, stores minerals, and allows movement

What is the function of the Endocrine System?

produces hormones that regulate and coordinate processes/organs in the body

What is the function of the Muscular System?

movement of the body

What is the function of the Reproductive System?

produces gametes and offspring

What limits cell size?

It is limited by its surface area to volume ratio. If it becomes to large it needs more food but it cannot receive the food fast enough. smaller cells have a greater surface area to volume ratio and that they can diffuse in and out of cells quickly

How does the exchange of substances take place in marine animals/unicellular organisms

they can directly exchange substances by diffusion since they are in direct contact with the external environment.

How does the exchange of substances take place in larger animals

through specialized exchange surfaces that are highly branched or folded

What is an endotherms?

warmed by heat generated by metabolism

What is an ectotherms?

gains heat from external sources

What is a conformer?

the internal environment matches the external environment

What is a regulator?

maintains a constant internal environment while the external environment changes

What is homeostasis?

Maintenance of a constant internal environment. Even when external conditions change

What is negative feedback control mechanisms?

maintains homeostasis, works by reducing a stimulus

What is positive feedback control mechanisms?

drives a process to completion by increasing a stimulus

How does thermoregulation occur in the human body?

If body temperature increases, the hypothalamus activates a cooling mechanisms that will dilate blood vessels and sweat glands will respond which will lead to body temperature decreasing. If body temperature decreases, the hypothalamus activates a warning mechanisms that will contract blood vessels and shivering will occur to increase body temperature.

What is a homeotherm?

Species that maintain a constant body temperature

What is a poikilotherm?

species who do not maintain a constant body temperature

What is the difference between a homeotherm/poikilotherm and endotherm/ectotherm

homeotherm/poikilotherm is the stability of body temperature and endotherm/ectotherm is the source of heat