UNIT 4 - ORGANIZATION AND REGULATION OF BODY SYSTEMS Flashcards
what are tissues?
-a group of cells with a similar function
-extracellular matrix helps carry out the function
what are the 4 major tissue types?
-epithelial
-connective
-muscle
-nervous
what are the characteristics of connective tissue?
-binds + supports
-has 3 main components
-can be fluid or solid (blood vs bone)
-has 3 protein fibres that can create its matrix
-has 3 types
what are the 3 types of connective tissue?
-fibrous CT
-supportive CT
-fluid CT
what are the 3 protein fibres that can create the matrix of CT?
-collagen fibres (flexible + strong)
-elastic fibres (stretch + recoil)
-reticular fibres (thin + branched collagen fibres)
what are the 2 forms of fibrous CT?
-loose (less fibers more ground substance)
-dense (more fibers less ground substance)
what kinds of loose connective tissue are there?
-reticular CT (kidney + lymph nodes)
-adipose tissue (under skin + in bone)
what is the main purpose of loose fibrous connective tissue?
-support epithelium + internal organs
what are characteristics of adipose tissue?
-stores fat
-little matrix (cells are large)
-adipocytes are the cells that store fat
-functions in energy storage, insulation, and cushioning
-found under skin and around some organs (stroma of kidney + testes)
where is dense connective tissue found?
-tendons (muscle to bone)
-ligaments (bone to bone)
what fiber largely makes up dense CT?
-collagen (tightly packed)
what are the 2 types of supportive CT? what do they function in?
-bone + cartilage
-structure, shape, protection, and leverage for movement
what are the characteristics of cartilage?
-has chondrocytes in lacunae
-solid but flexible matrix
-lacks a direct blood supply (avascular)
what are the 3 types of cartilage?
-hyaline
-elastic
-fibro
what is distinct about hyaline cartilage? where do you find it?
-fine collagen fibres in the matrix
-tip of the nose, ends of long bones, fetal skeleton
what is distinct about elastic cartilage? where do you find it?
-abundant elastic fibres in the matrix
-in the outer ear
what is distinct about fibrocartilage? where do you find it?
-abundant strong collagen fibres in the matrix
-intervertebral discs
what are the characteristics of bone?
-most rigid connective tissue
-matrix contains collagen and calcium salts
-2 types of bone tissue
what are the 2 types of bone tissue?
-compact bone
-spongy bone
what are the characteristics of compact bone?
-made of cylindrical structural units called osteons
-osteons have a central canal with blood vessels + nerves
-osteocytes are in lacunae
-make up the shafts of long bones
what are the characteristics of spongy bone?
-lighter than compact bone
-very strong
-in the ends of long bones
what are the two types of fluid connective tissue?
-blood
-lymph
what are the characteristics of blood?
-fluid matrix called plasma
-cellular components are “formed elements”
-3 formed elements
what are the 3 formed elements in blood?
-RBC (erythrocytes) (carry oxygen)
-WBC (leukocytes) (fight infection)
-Platelets (thrombocytes) (clot blood)
what is lymph?
-contains WBCs
-derived from the fluid surrounding tissues
-lymphatic vessels absorb excess interstitial fluid
where is lymph returned?
-to the cardiovascular system
-subclavian veins level
what are the characteristics of muscle tissue?
-specialized to contract
-moves the body
-cells are muscle fibres
-3 types
what are the 3 types of muscle tissue?
-skeletal
-smooth
-cardiac
what are the characteristics of skeletal muscle?
-attached by tendons
-contraction moves the skeleton
-voluntarily controlled
-very long muscle fibers with multiple nuclei
-striated
why do skeletal muscle fibres contain multiple nuclei?
-more DNA
-more transcription
-more mitochondria can be built
what are the dark bands in skeletal muscle?
-A bands
-contains thick and thin filaments
what are the light bands in skeletal muscle?
-I bands
-contains thin filaments only
what are the characteristics of smooth muscle?
-no striations
-spindle shaped cells with 1 nucleus
-involuntary control
-in the walls of viscera (large organs)
what are the characteristics of cardiac muscle?
-only in the walls of the heart
-striated
-involuntary control
-single nucleus cells
-cells are connected by intercalated discs
what is contained within intercalated discs?
-desmosome junctions (anchoring)
-gap junctions (synchronization)
what are the characteristics of nervous tissue?
-conducts nerve impulses
-consist of neurons and glial cells
-functions in sensory input, integration, and motor output
what is the structure of a neuron?
-3 parts
-dendrites (carry info towards the cell body)
-cell body (contains the nucleus + organelles)
-axon (conducts nerve impulses away from the cell body)
what are the characteristics of glial cells?
-outnumber neurons (9:1)
-more than half the brains volume
-support and nourish neurons
-many types
what covers the axon of a neuron?
-myelin sheath
what cells create the myelin sheath in the PNS? CNS?
-schwann cells (PNS)
-oligodendrocytes (CNS)
what are the main types of glial cells?
-microglial cells
-ependymal cells
-astrocytes
-schwann cells
-oligodendrocytes
what are the characteristics of epithelial tissue?
-covers body surfaces + lines body cavities + creates glands
-protects
-made of tightly packed cells
-basement membrane
-free surface (lumen)
how are epithelial tissues named?
-shape of cells
-# of cell layers
how are epithelial tissues named for the # of cell layers?
-simple = 1 layer
-stratified = more than 1 layer
how are epithelial tissues named for the shape of cells?
-squamous (flattened cells)
-cuboidal (cubed cells)
-columnar cells (rectangular cells)
what is the main function of simple squamous epithelium? where is it mainly found?
-gas exchange
-sacs of lungs
-increase surface + decrease thickness for efficiency
where can you find simple cuboidal epithelium?
-salivary glands
-kidney tubules
where can you find simple columnar epithelium? how is the surface expanded?
-digestive tract + uterine tubes
-microvilli
what are the characteristics of pseudostratified epithelium?
-appears stratified because nuclei do not line up (actually simple)
-often has cilia to move mucus
-found in windpipe + trachea linings
where can you find stratified squamous epithelium?
-outer layer of skin (epidermis)
-lining of the mouth
-esophagus
-outer portion of cervix
what are the characteristics of transitional epithelium?
-cells change shape from cuboidal to squamous in response to tension (stretching)
-found in the urinary bladder
what are the characteristics of glands?
-make and secrete products
-2 types
what are the 2 types of glands?
-exocrine
-endocrine
how do exocrine glands function?
-secrete into ducts onto a body surface or cavity
-one cell (goblet cell)
-multiple cells (sweat/mammary gland)
how do endocrine glands function?
-secrete products into the bloodstream
-no ducts
what is an organ?
-a group of 2 or more different tissues performing a common function
what lines organs and cavities?
-membranes
what is included in the integumentary system?
-skin
-hair
-nails
-glands
what are the functions of the integumentary system?
-protects underlying tissues from trauma, pathogen invasion, and water loss
-helps regulate body temp.
-touch + temp. receptors (aware of surroundings)
what tissue types are present in the integumentary system?
-all 4!
what are the different layers of the skin? how much of our body weight is skin?
-epidermis + dermis
-hypodermis (subcutaneous)
-15% of total body weight
what is the purpose of the hypodermis?
-attaches skin to bones
what are the characteristics of the epidermis?
-thin outer layer
-stratified squamous epithelium
-contains many different cells that perform different functions
what type of cells are in the deepest layer of the epidermis? what is their purpose?
-stem cells
-produce new epidermal cells
what must happen if stem cells are destroyed?
-skin must be replaced
-autograft or allograft
what is an autograft?
-skin from another area of the body
what is an allograft?
-skin from another person
what are the cells of the epidermis?
-keratinocytes
-langerhans/dendritic cells
-melanocytes
-merkel cells
-carotene
-hemoglobin
what are the characteristics of keratinocytes?
-upper layer of epidermis
-dead + filled with keratin
-waterproof barrier (no loss + no gain)
what is the purpose of langerhans/dendritic cells?
-WBC
-phagocytize infectious agents
what are the characteristics of melanocytes?
-produce melanin (skin pigment)
-protects from UV light
-each person has = # of melanocytes but the amount of melanin produced varies
what is the purpose of merkel cells?
-mechanoreceptors
-essential for light touch + sensation
what cells in the epidermis contribute to skin colour (besides melanocytes)?
-carotene
-hemoglobin
what are the characteristics of the dermis?
-thick inner layer
-dense fibrous connective tissue
-collagen and elastic fibres for strength and elasticity
-has blood vessels, sensory receptors, and glands
what are the sensory receptors in the dermis specialized for?
-touch
-pressure
-pain
-temperature
what are the characteristics of the subcutaneous layer?
-not part of the skin
-loose adipose tissue
-stores energy
-insulates
-protects
what are the accessory organs of the skin?
-nails
-hair
-glands
what is the purpose of nails?
-offer a protective covering of the fingers and toes
what are the parts of the nail?
-nail root (where the nail grows from to cover the nail bed)
-cuticle (covers the nail root)
-lunula (white half moon at the nail base)
what are the main parts of the hair?
-hair follicle
-hair shaft
-hair bulb
-dermal papilla
what are hair follicles?
-epidermal structures that surround the hair itself
what is the hair shaft?
-portion of hair that protrudes from the skin
where does the colour of hair come from? what happens to these as you age?
-melanin from melanocytes
-melanocytes produce less pigment (hair turns grey)
what are arrector pili muscles?
-attached to the hair follicle
-smooth muscle that contracts to give goosebumps
what is the hair bulb?
-lowest part of the hair strand
-thicker than the rest of the strand
what is the dermal papilla?
-cells that regenerate and create the hair shaft
what is the hair cuticle?
-layer of dead cells that form a protective layer around the hair strand
what is the cortex of the hair?
-main bulk of pigment for the hair
-long keratin filaments
what are the main glands in the skin?
-sebaceous glands
-sudoriferous glands
what is the function of the sebaceous glands?
-produce sebum to soften the hair and skin
how is acne formed?
-inflammation of the sebaceous glands
what does sebum delay?
-bacterial growth
what is the function of the sudoriferous glands?
-help to regulate body temp
what are the 2 main body cavities?
-ventral
-dorsal
what does the ventral cavity contain?
-thoracic, abdominal, and pelvic cavities
what separates the thoracic and abdominal cavities?
-diaphragm
what does the dorsal cavity contain?
-cranial cavity and vertebral canal
what does the thoracic cavity contain?
-heart, lungs, and esophagus
what does the abdominal cavity contain?
-stomach, liver, spleen, pancreas, gallbladder, and intestines (digestive organs)
what does the pelvic cavity contain?
-reproductive and other organs
what are the 4 types of body membranes?
-serous membranes
-mucous membranes
-synovial membranes
-meninges
what parts of the body are lined by serous membranes?
-closed cavities
-surface of organs contained within those cavities
what are 3 examples of serous membranes in the body?
-parietal + visceral pleura (thoracic cavity + lungs)
-pericardium (heart, forms the pericardial sac)
-peritoneum (abdominal cavity)
what parts of the body are lined by mucous membranes?
-open cavities (digestive, respiratory, urinary, and reproductive systems)
what are characteristics of mucous membranes?
-epithelium that overlies loose fibrous CT
-contains goblet cells to secrete mucus (prevents bacteria from invading the body)
what parts of the body are lined by synovial membranes?
-freely moveable joints
what are characteristics of synovial membranes?
-loose connective tissue
-secrete synovial fluid for lubrication
what parts of the body are lined by meninges?
-brain and spinal cord (dorsal cavity)
what are the characteristics of meninges?
-composed of connective tissue
-3 layers
what are the 3 layers of meninges?
-dura mater (white outer tough CT)
-arachnoid (thin middle cobweb layer)
-pia mater (inner)
what is meningitis?
-inflammation of the meninges
what is homeostasis?
-the state of a steady internal environment maintained by the body
what conditions are kept steady by homeostasis?
-blood glucose
-pH
-body temp.
-oxygen
what happens if the conditions vary too much?
-illness
what are the parts of the internal environment?
-blood
-interstitial fluid
what is bloods function?
-delivers oxygen and nutrients to the tissues and carries away carbon dioxide and wastes
what is interstitial fluids function?
-exchange substances with surrounding cells
which 2 systems are the main coordinators of the other organ systems? which provides long term effects and which provides short term effects?
-nervous system (short)
-endocrine system (long)
how does the endocrine system maintain control?
-secretes hormones into the blood which travel to target cells and tissues
what are the 2 homeostatic mechanisms?
-negative feedback (primary)
-positive feedback
how does negative feedback act as a homeostatic mechanism?
-uses a sensor and a control center
-the systems output brings down the change (opposite direction of original stimulus)
-ex: temp. regulation
how does positive feedback act as a homeostatic mechanism?
-increases the change (same direction of original stimulus)
-can be harmful in some situations (ex: fever)
-helpful in other situations (ex: childbirth)
how does childbirth utilize the positive feedback mechanism?
-fetus’ head pushes against the cervix (stimulus)
-brain secretes oxytocin as a response (stronger contractions)
-stronger contraction increases oxytocin release
-birth of the child stops the positive feedback
