Chapter 33; power point Flashcards
All animals besides sponges have some type of _____
symmetry
All animals besides sponges have what three things?
Symmetry, tissues, and size and metabolism
What are the two main types of symmetry?
Radial and bilateral
What is radial symmetry?
Body parts are arranged around central axis; Can be bisected into two equal halves in any 2-D plane
What is bilateral symmetry?
Body has right and left halves that are mirror images; Only the sagittal plane bisects the animal into two equal halves
What are all animals besides sponges called?
Eumetazoa
What are sponges called?
Parazoa
What does a sagittal plane do?
Divides the body into left and right portions
What does a midsagittal plane do?
Divides the body exactly in the middle, making two equal right and left halves.
What does a frontal plane/ coronal plane do?
Divides the body into front and back
What does a transverse/ horizontal plane do? What is it sometimes called?
Divides the animal into upper and lower portions. This is sometimes called a cross section, and, if the transverse cut is at an angle, it is called an oblique plane.
Small, unicellular organisms get nutrients through what?
Diffusion
Cell size is constrained by what?
Surface area-to-volume ratio
Define basal metabolic rate
Average amount of energy used by an organism in a non-active state
Excess energy is given off as ___
heat
Do smaller or larger endothermic animals have a higher BMR?
Smaller
Do active or inactive animals have a higher BMR?
Active
Energy from nutrients is used in the animal body to fuel what?
Anabolic reactions
A tissue consists of what?
A group of closely associated, similar cells that carry out specific functions
What are the four main types of animal tissues?
Epithelia, connective tissues, muscles, and neurons
What do epithelia tissues do?
Line cavities, open spaces, and surfaces
What do connective tissues do?
Connect tissues together, provide support
What do muscles do?
Generate movement
What do neurons do?
Generate and send electrical signals
What are the three types of epithelial cells?
Squamous, cuboidal, and columnar
Describe the two surfaces of epithelial tissues
One surface is exposed; it covers the body (outer layer of skin) or lines a cavity in a hollow organ, such as the lumen of the intestine. The other surface attaches to underlying tissue by a noncellular basement membrane
What are the three types of arrangements of epithelial cells?
Simple, pseudostratified, and stratified
Simple epithelium tissues are usually located where?
Where substances are secreted, excreted, absorbed, or diffused
What may epithelium tissues have and why?
May have cilia that move materials over the tissue surface
Stratified epithelium has how many layers?
Two or more
What does stratified epithelium do?
Protects underlying tissues
What is pseudostratified epithelium?
Epithelium that appears layered, but not every cell extends to the exposed surface of the tissue
What two things do epithelial cells make up?
Glands and membranes
What are glands?
One or more epithelial cells that secrete a product such as sweat, milk, mucus, wax, saliva, hormones, or enzymes
What are the two types of glands?
Endocrine and exocrine glands
Define exocrine glands and give 2 examples
Glands that secrete products onto a free epithelial surface, typically through a duct (Example: goblet cells, sweat glands)
Define endocrine glands and give an example
Glands that release hormones into the interstitial fluid or blood (Example: thyroid gland)
Define membranes
A sheet of epithelial tissue and a layer of underlying connective tissue
What are the two types of membranes?
Mucous membrane and serous membrane
Define mucous membrane
Lines a body cavity that opens to the outside of the body
What keeps mucous membrane from dying?
Goblet cells secrete mucus that lubricates the tissue and protects it from drying
Define serous membrane
It secretes fluid into the body cavity it lines – it consists of simple squamous epithelium over a thin layer of loose connective tissue
Describe connective tissues in detail
Cells are embedded in an intercellular substance consisting of threadlike fibers scattered through a matrix of polysaccharides secreted by the cells
What are the seven main types of connective tissues?
Loose and dense connective tissues, Elastic connective tissue, Reticular connective tissue, Adipose tissue, Cartilage, Bone; Blood, lymph, and tissues that produce blood cells
What are connective tissue cells called?
Fibroblasts
The connective tissue matrix is usually composed of _____ _____
ground substance
What is ground substance?
Found in connective tissues, usually composed of some combination of collagen, elastic, or reticular fibers
What are the three types of fibers?
Collagen, elastic, and reticular
The structure and function of each kind of connective tissue is determined in part by what?
By the properties of its intercellular substance
Is the matrix of connective tissues cellular or noncellular?
Noncellular
Describe collagen fibers
Composed of tough fibrous proteins that remain intact when tissue is stretched
Describe elastic fibers
Branch and form networks; composed of elastin; return to original size when stretched
Describe reticular fibers
Networks of tissues; Thin, branched fibers consisting of collagen and some glycoprotein
What do fibroblasts do?
Produce the fibers, protein and carbohydrate complexes, of the connective tissue matrix
Where are fibroblasts especially active/ important?
In developing tissues and important in healing wounds
Describe macrophages
The body’s scavenger cells; they wander through connective tissues, cleaning up cell debris, engulfing foreign matter, including bacteria
Describe loose connective tissues
Form the subcutaneous layer that attaches skin to muscles and other structures (e.g., nerves) and is a thin filling between body parts and serves as a reservoir for fluid and salts
What serves as a reservoir for fluids and salts?
Loose connective tissues
Fibers run in all directions through what?
The semifluid matrix of loose connective tissues
Describe dense connective tissues
Found in the lower layer of the skin, it’s strong, but less flexible than loose connective tissue, and collagen fibers predominate
Collagen fibers predominate in what kind of connective tissue?
Dense connective tissues
What two things consist of dense connective tissue in a definite pattern?
Tendons and ligaments
What type of tissue is found in the lower layer of the skin?
Dense connective tissues
What is elastic connective tissue mainly composed of?
Consists mainly of bundles of parallel elastic fibers
Where is elastic connective tissue found?
Found in structures that must expand and then return to their original size, such as lung tissue and the walls of large arteries
What is reticular connective tissue mainly composed of?
Interlacing reticular fibers
What does reticular connective tissue do and where is it found?
Forms a supporting internal framework in many organs, including the liver, spleen, and lymph nodes
What does adipose connective tissue do?
Stores fat and release it when fuel is needed for cellular respiration
Where is adipose connective tissue found?
In the subcutaneous layer and in tissue that cushions internal organs
Describe cartilage (connective tissue).
Firm elastic tissue consisting of chondrocytes that lie in small cavities in lacunae and secrete a hard, rubbery matrix and collagen fibers.
Where is cartilage found in all vertebrates?
It supports the skeleton in embryonic stages of all vertebrates
What body parts is cartilage found in humans?
The external ear, the tip of the nose, walls of respirator passages, the ends of some bones, and vertebral disks
What is the main vertebrate skeletal tissue?
Bone
What does bone (a connective tissue) mostly consist of?
Consists mostly of calcium salts and collagen secreted by osteocytes
What’s an example of a highly vascular tissue with a blood supply?
Bone
What do canaliculi contain and why?
Canaliculi contain cytoplasmic extensions for communication between osteocytes (bone cells)
What type of bone is on the outside and what type is on the inside?
Compact bone surrounds spongy bone
Describe bone
A large, central marrow cavity contains yellow marrow (fat) and red marrow that produces blood cells
What produces blood cells?
Red bone marrow
Blood vessels and nerves run through what inside bone?
Through the Haversian canal within each osteon of compact bone.
Describe the bone matrix
Rigid and hard
How do osteocytes communicate with each other?
They communicate with one another by way of cytoplasmic extensions that extend through tiny canals (because they’re trapped in lacunae).
Osteocytes become trapped within ____
lacunae
What type of tissue is bone?
Connective
What does blood (a connective tissue) consist of?
Non-cellular plasma, red blood cells, white blood cells, and platelets
What is the purpose of non-cellular plasma in the blood?
Water, proteins, salts, and soluble chemical messengers
What is the purpose of red blood cells?
Oxygen transport
What is the purpose of white blood cells?
Defense
What is the purpose of platelets in the blood?
Clotting
What enables movement?
The contraction of muscle cells
What are muscle fibers? Why are they called that?
Long, cylindrical or spindle-shaped muscle cells. They’re called muscle fibers because of their length
What is within each muscle fiber?
Many thin, parallel contractile units (myofibrils) consisting of myosin and actin proteins
What are the three types of muscle tissue?
Skeletal, cardiac, and smooth
Describe skeletal muscle
Voluntary and striated
Describe cardiac muscle
Involuntary and not striated
Describe smooth muscle
Involuntary, striated, and intercalated disks
What is skeletal muscle?
Large muscle masses that are attached to bones of the body and move body parts
Describe skeletal muscle fibers
Long, with many nuclei
Describe the contraction of skeletal muscle
Has alternating light and dark transverse stripes (striations) that change relative sizes during contraction. Striated fibers contract rapidly but must relax and rest momentarily before contracting again
What is the main tissue of the heart?
Cardiac muscle
Describe cardiac muscle fibers
Each fiber has one or two nuclei, each fiber has striations, and they have specialized junctions where the fibers join
Describe the structure of cardiac muscle fibers
They join end to end, branch and rejoin to form complex networks
Where is smooth muscle found?
In the walls of the digestive tract, uterus, blood vessels, and many other hollow internal organs
Describe smooth muscle fibers
Each spindle-shaped fiber contains a single, central nucleus. They are not striated!
Give an example of smooth muscle cells in action
Example: When smooth muscle in the walls of arterioles contracts, the vessels constrict, raising blood pressure
What two things make up nervous tissues?
Neurons and glial cells
What do neurons do?
Some receive and transmit signals, others relay, process, and store information; some neurons transmit signals from the brain and spinal cord to the muscles and glands
What do glial cells do?
Support and nourish the neurons, destroy pathogens, and modulate transmission of impulses
What are the two cytoplasmic extensions of neurons?
Dendrites and a single axon
What do neurons consist of?
A cell body that contains a nucleus, dendrites, and an axon
What do dendrites do?
Receive and transmit signals to the cell body
What does an axon do?
It transmits signals away from the cell body
Where do neurons communicate?
At junctions called synapses
What makes up a nerve?
Many neurons bound together by connective tissue
What makes up an organ system?
An organized group of tissues and organs that perform a specialized set of functions
How many organ systems do humans have?
11 major organ systems that work together to carry out physiological processes
What is homeostasis?
A dynamic equilibrium in which conditions are maintained within narrow limits (in a steady state) by homeostatic mechanisms
What can challenge homeostasis?
Changes in the environment that affect normal conditions within the body, or stressors, continuously challenge homeostasis
Homeostasis aims to keep internal conditions around a ________
set point
What is it called when an organism’s homeostatic set point changes?
Alteration
What is acclimatization?
Changes in one organ system to maintain a set point in another organ system (ex: altitude)
What is alteration?
When an organism’s homeostatic set point changes
What are the two categories of ways organisms maintain homeostasis?
Conformers vs regulators
Describe conformers and give an example
Conformers vary some of their internal states with their surroundings; for example most marine invertebrates conform to the salinity of the surrounding sea water
Describe regulators and give an example
Regulators (such as mammals) have complex homeostatic mechanisms that maintain relatively constant internal conditions despite changes in the outside environment
Define positive feedback loop
Maintains and possibly strengthens a response to a stimulus
Give a good example and a bad example of positive feedback loops
Oxytocin during labor (good) and blood pressure drops with hemorrhage (bad)
What is a negative feedback loop?
Counteracts any internal changes (reverses the direction of the change)
What are examples of negative feedback loops?
Temperature, glucose, pH, and blood calcium
Describe the negative feedback loop of glucose
The response of the integrator is opposite to the input of the sensor, so if the glucose concentration
in the blood is too low, alpha cells in the pancreas secrete a hormone that increases glucose concentration.
What is thermoregulation?
The process of maintaining body temperature within certain limits despite changes in the surrounding temperature
What is estivation?
A state of torpor caused by lack of food or water during periods of high temperature
What is hibernation and how do animals survive it?
Hibernation is a long-term torpor in response to winter cold and scarcity of food, and animals store unsaturated fats to use as energy sources
What is torpor? When does it happen and why?
It’s a short-term state in which metabolic rate decreases, it occurs in many small endotherms when stressed by cold, and it saves the energy that the animal would use to maintain a high body temperature
What is acclimatization? What’s an example?
When animals adjust to seasonal changes. Example: thickening of a dog’s coat in winter
Where are temperature receptors located?
Receptors located in the hypothalamus and in the spinal cord regulate temperature
How do temperature receptors produce heat and coldness?
Produce heat: hormones, muscle contraction, or shivering. Lower temperature: panting; dilation of skin capillaries, and sweating
What are the physiological mechanisms of endotherms?
Physiological mechanisms: the regulation of heat production and heat exchange with the environment
What are endotherms?
Birds and mammals with homeostatic mechanisms that maintain body temperature despite changes in the external temperature
What is an advantage to being an endotherm?
High metabolic rate, which allows rapid enzyme activity and responses to stimuli
What’s a disadvantage to being an endotherm?
High energy cost of thermoregulation during inactive periods
What’s a structural adaptation of endotherms? Examples
Insulation, like insulating feathers of birds, hair of mammals, and insulating layers of fat
What’s are examples of behavioral adaptations of endotherms?
Like squirrels shading their bodies with their tails; elephants spray themselves with water
What are ectotherms?
Animals that depend on the environment for their body heat; body temperature is determined mainly by the changing temperature of their surroundings
What are the advantages of ectotherms?
Very little energy is used to maintain a high metabolic rate
What are the disadvantages of ectotherms?
Daily and seasonal temperature conditions may limit activity
What are the behavioral advantages of ectotherms?
Many ectotherms use behavioral strategies to adjust body temperature; others migrate to warmer climates during the winter, or hibernate
