chapter 31 quiz Flashcards
Tissues are
Collections of specialized cells of the same or a similar type that perform a common function in the body
The four tissue types are:
Epithelial
Connective
Muscular
Nervous
Epithelial Tissue (epithelium)
Forms a continuous layer over body surfaces
Lines body cavities
Forms glands
Epithelial cells may be connected to one another by
Tight junctions
Adhesion junctions
Gap junctions
Functions of Epithelial tissue
Protection Secretion Absorption Excretion Filtration
Simple Epithelia
A single layer of cells
Simple Epithelia is Classified according to cell type
Squamous epithelium
Cuboidal epithelium
Columnar epithelium
Squamous epithelium
flattened cells
Cuboidal epithelium
cubed shaped cells
Columnar epithelium
cells representing columns
Stratified Epithelia
Layers of cells
Glandular Epithelia
Secretes a product
gland
can be a single epithelial cell or can contain many cells.
Exocrine glands
Secrete products into ducts or cavities
Endocrine glands
Secrete products internally so they are transported into the bloodstream
Connective tissue
Diverse in structure and function but all types have
Specialized cells
Ground substance – Noncellular material
Protein fibers
Collagen fibers
contain collagen providing strength and flexibility
Reticular fibers
contain thin, highly branched collagen fibers
Elastic fibers
contain elastin, not as strong but more elastic than collagen
connective matrix
ground substance plus fibers
Three categories of connective tissue are
Fibrous
Supportive
Fluid
Fibrous Connective Tissue
Consists of:
Fibroblast cells
A jellylike matrix containing collagen and elastic fibers
Loose fibrous connective tissue
Allows organs to expand
Supports epithelium and many internal organs
Forms protective covering over internal organs
Adipose tissue
Stores energy
Insulates the body and provides padding
Mostly white, but brown in newborns due to increased numbers of mitochondria
Dense fibrous connective tissue
Strong connective tissue
Tendons – connect muscle to bone
Ligaments – connect bones to other bones at joints
Supportive Connective Tissue
Cartilage
Bone
Cartilage
Classified according to type of collagen and elastic fibers found in the matrix (hyaline cartilage, elastic cartilage, fibrocartilage)
Cartilage cells lie in small chambers (lacuna) in the matrix.
Cartilage lacks a direct blood supply and heals very slowly.
Hyaline
Consists of very fine collagen fibers
Matrix is translucent
Found in nose and ends of long bones and ribs
Elastic
More elastic fibers than hyaline
More flexible
Found in framework of outer ear
Fibrocartilage
Matrix contains strong collagen fibers
Found in structures that withstand tension and pressure
Found in pads between vertebrae in backbone
Bone
Most rigid connective tissue
Matrix is inorganic salts deposited around protein fibers
Bone cells are located in lacunae.
Lacunae arranged in concentric circles within osteons around tiny tubes (central canals)
Bone Consists of hard matrix of inorganic salts
Mostly calcium
Provides rigidity
Bone Deposited around protein fibers
Especially collagen
Provides elasticity and strength
Types of Bone
compact
spongy
Compact bone
Makes up shaft of long bone
Consists of cylindrical units called osteons
Blood vessels in central canal carry nutrients
Spongy bone
Makes up ends of long bone
Contains bony bars and plates separated by air spaces
Site of red bone marrow, which produces blood cells
Fluids
Blood
Lymph
Blood
A connective tissue in which cells are embedded in a liquid matrix (plasma)
Red blood cells – oxygen transport
Small disk-like cells without nuclei
White blood cells – immune response
Larger than red blood cells and have a nucleus
Platelets – involved in the clotting process
Fragments of larger cells present only in bone marrow
Blood functions
Transports nutrients and oxygen to cells
Removes carbon dioxide and other wastes
Helps distribute heat and plays a role in fluid, ion, and pH balance
Lymph
A fluid connective tissue located in lymphatic vessels
Lymphatic capillaries called lacteals absorb fat molecules from the small intestine.
Muscular (Contractile) Tissue
Contractile cells containing actin and myosin filaments
Cells are called muscle fibers.
Three types of muscle tissue
skeletal muscle
smooth (visceral) muscle
cardiac muscle
Skeletal Muscle
Voluntary – Long, striated fibers, multinucleated
Smooth (Visceral) Muscle
Involuntary – No striations
cardiac muscle
Striated, but mostly involuntary
Cells are bound to each other by intercalated disks.
Have one single, centrally placed nucleus
What are some functions of the Nervous system?
Sensory input
Data integration
Motor output
Nervous Tissue
Conducts electrical impulses
Conveys information from one area to another
types: Neurons, Neuroglia
Neurons
Transmit information
Consist of dendrites, a cell body, and an axon
An axon and its myelin sheath, if it has one, is called a fiber.
Outside the brain and spinal cord, fibers bound by connective tissue form nerves.
Neuroglia
Support and nourish neurons Neuroglia in brain include Microglia Astrocytes Glial cell-derived growth factor is being studied as a possible Parkinson disease treatment. Oligodentrocytes
Organ
Composed of two or more tissue types working together for a particular function
organ system
Composed of various organs that cooperate to carry out a general process
Example: digestion of food
Body Cavities:
Dorsal cavity (toward the back)
Ventral cavity (toward the front) is divided into
Dorsal cavity (toward the back)
It contains the cranial cavity and the vertebral canal.
The brain is in the cranial cavity.
The spinal cord is in the vertebral canal.
Ventral cavity (toward the front) is divided into
The thoracic cavity (includes heart and lungs),
The abdominal cavity (most other internal organs), and
The pelvic cavity (urinary bladder, female reproductive organs, certain male reproductive organs)
The organ systems of the human body contribute to
homeostasis
Importance of Homeostasis for Astronauts
The fact that astronauts need special suits to survive in space reminds us that the internal environment of our bodily functions must stay within normal limits.
Example: Enzymes function best at around 37°C
An astronaut depends on artificial systems in addition to natural systems to maintain homeostasis.
Examples of Homeostatic Regulation
The organ systems of the human body contribute to homeostasis.
The digestive system
Takes in and digests food
Provides nutrient molecules that replace used nutrients.
The respiratory system
Adds oxygen to the blood
Removes carbon dioxide
The liver and the kidneys
Store excess glucose as glycogen
Later, glycogen is broken down to replace the glucose used.
The hormone insulin regulates glycogen storage.
The kidneys
Under hormonal control as they excrete wastes and salts that can affect the pH of the blood
Homeostatic Control
Homeostasis is, to a degree, controlled by hormones.
But is ultimately controlled by the nervous system
Negative feedback
is the primary homeostatic mechanism that keeps a variable close to a set value.
The sensor detects change in environment.
Regulatory center initiates an action to bring the conditions back to normal.
Positive feedback
is a mechanism that brings about an ever greater change in the same direction.
Childbirth process
Positive Feedback
Does not result in equilibrium
Does not occur as often as negative feedback
The Integumentary System
Functions of skin
Largest and most conspicuous organ system
Covers and protects underlying body regions
Regulates body temperature
Contains sensory receptors
Involved in exchange of gases with environment in small aquatic animals
Manufactures precursors to vitamin D after UV exposure
Skin and its derivatives make up the integumentary system
Regions of the Skin
Epidermis, Dermis, Subcutaneous Layer
Epidermis
Outer, thinner region
Stratified squamous epithelium
New cells are pushed outward, become keratinized, and are sloughed off.
Melanocytes produce melanin (pigment).
UV radiation can cause mutations in the DNA of skin cells, leading to skin cancer.
Dermis
Deeper and thicker than epidermis Fibrous connective tissue containing elastic and collagen fibers contains: Receptors Nerve fibers Blood vessels
Subcutaneous Layer
Loose, connective tissue located below dermis, also known as hypodermis
Accessory Structures of Human Skin
Nails, Hair follicles, Sweat glands
Nails
Grow from nail root and form protective covering of distal portion of fingers and toes
Hair follicles
Begin in the dermis and continue through the epidermis
Contain oil glands (sebaceous glands) which secrete sebum
Lubricates the hair within the follicle as well as the skin
Sweat glands
Present in all regions of the skin
Begin in dermis and open either to a hair follicle or to the surface of the skin
Function to help maintain constant body temperature
