Lab 7 Flashcards
Muscle tissues
- function
- muscle cells called what?
- highly cellular tissues that use ATP to generate force to produce contractions.
- produces most kinds of body movements, maintains posture and generates heat.
- Muscle cells are called muscle fibers, as these cells have an elongated shape
The cytoplasm of the muscle cell is the ____
Cell membrane is referred to as the ______
Cytoplasm = sarcoplasm
Cell membrane = sarcolemma.
3 types of muscle tissue found in the human body
skeletal muscle tissue
smooth muscle tissue
cardiac muscle tissue
Skeletal Muscle Tissue
- long, thick, cylindrical cell
- ends of fibers are blunt
- multiple, nuclei, peripherally located
- contains striations
- sarcomeres are the functional units
- attached to bones and when these muscles contract, movement of the skeleton occurs
LOCATION: skeleton (skeletal muscles
FUNCTION: moves bones of skeleton
CONTROL: voluntary
Unique: number and position of nuc
Smooth Muscle Tissue
- shorter spindle-shaped cells, with tapered ends
- cells are tightly packed in a sheet-like arrangement
- single oval nucleus, centrally located
- no striations
LOCATION: GI tract, uterus, eye, blood vessels (within the walls of hollow organs, such as blood vessels and organs of the digestive, urinary, respiratory and reproductive tracts)
FUNCTION: peristalsis, blood pressure, pupil size, erect hair. (contraction moves materials along internal passageways and regulates the diameter of blood vessels and respiratory tracts)
CONTROL: involuntary
Unique: No striations, spindle with tappered ends
Cardiac Muscle Tissue
- cells that branch in an irregular pattern
- striations.
- one nucleus, oval and centrally located
- intercalated discs where cells join end-to-end
LOCATION: wall of the heart
FUNCTION: pump blood continuously
CONTROL: involuntary
Unique: fibers branch, intercalated disc
striations
- transverse bands or striations, that are visible as light and dark bands within each fiber
- result of the arrangement of parallel structures called myofibrils within the sarcoplasm.
sarcomeres
Structural unit of myofibril
-parallel structures make up myofibril, these are in turn made up of the orderly arrangement of even smaller structures called myofilaments, which are arranged in compartments called sarcomeres
intercalated discs
- regions where the cell membranes of adjacent cells contact each other and contain desmosomes and gap junctions
- allow for cohesion and rapid electrical conduction
- vital roles in bonding cardiac muscle cells together and in transmitting signals between cells
two major divisions of the nervous system
The central nervous system
- the brain
- spinal cord
The peripheral nervous system
-all nervous tissue outside the brain / spinal cord
Neurons
• structural and functional units of nervous tissue
• largest and most prominent Ner.Sys cell
• convert stimuli into electrical signals (action potentials)
• Contain
- cell body (soma): nuc, mito, nissil body, ribos, neurofibrils
- dendrites: tapering, branched processes, receive stimuli or information from other neurons
- axon: cytoplasmic process, conduct information to other cells and is often referred to as a nerve fiber
Nissl bodies
aggregations of rough endoplasmic reticulum. important elements of the cytoskeleton
the manufacture and release of proteins and amino acids.
neurofibrils
found in soma. bundles of protein filaments which are important elements of the cytoskeleton.
play a role in the transport of proteins and other substances within the cytoplasm.
myelin
• a fatty sheath, protects and insulates the axon and also increases the speed of conduction of nerve impulses
• PNS: myelin sheath formed by Schwann cells
• CNS: myelin sheath formed by oligodendrocytes
• Schwann cells and oligodendrocytes are types of neuroglia cells.
•
nodes of Ranvier
- small gaps in the myelin sheath where the plasma membrane of the axon is exposed
- enable the nerve impulse to jump from node to node, hence increasing the speed at which an impulse travels.
telodendrites (axon terminals)
fine branched endings of the axon
grey matter and white matter
Grey:
- cell bodies
- thin outer layer of the brain surface and as a “butterfly-shaped”
- centre of the spinal cord
- dendrites, unmyelinated axons, axon terminals, neuroglia
White:
- myelinated axons of neurons
- this is the location of dense collections of whitish-coloured myelinated axons
- layer iside bran
- outside of spinal chord
ganglia
- contains clusters of neuron cell bodies
- ovoid structures containing cell bodies of neurons and glial cells supported by connective tissue. Ganglia function like relay stations - one nerve enters and an other exits.
3 covering and lining membranes
mucous, serous and cutaneous
continuous multicellular sheets composed of an epithelium bound to an underlying layer of connective tissue
Mucous membranes
- line body cavities that open to the exterior such as those of the hollow organs of the digestive, respiratory, reproductive and urinary tracts.
- moist membranes
- various types of epithelia.
- Many contain goblet cells/multicellular mucous glands.
- Ex:
Serous membranes
- moist membranes
- line the walls (parietal layer) and cover organs (visceral layer) within the closed ventral body cavities - pericardial, pleural and abdominopelvic cavities.
- A serous membrane consists of a simple squamous epithelium resting on a thin layer of areolar connective tissue.
- Serous fluid is produced by the serous membranes and acts to lubricate the surfaces to reduce friction.
cutaneous membrane
- is the skin which is exposed to the air and is a dry membrane.
- The skin is part the integumentary system
organ system
Organs that work together to perform a common function
integumentary system
complex group of organs that protects the human body from the external environment. This system is composed of the skin and its associated structures such as glands, hair and nails.
Skin function
- protection of underlying body parts;
- excretion of water, salts and wastes
- regulation of body temperature
- detection of sensory information, such as touch, temperature, pain.
skin is composed of two distinct regions
epidermis - a superficial region
dermis - deeper region
*note that the hyperdermis (subcutaneous layer) is part of the integument system but is NOT a part of skin
Epidermis
- stratified squamous epithelium
- where the epidermis is thickest, it is made up of five layers
- thickest on the palms of the hands and soles of the feet.
- thinnest on the tympanic membrane (the eardrum) and over the eyelids.
- stratum corneum - outermost layer filled w keratin
- stratum basale - deepest epidermal layer, single row of cells that are undergoing mitosis.
- As the cells move into the more superficial layers, they begin to flatten, fill with keratin and die.
- no blood vessles, relies on diffusion from dermis
Dermis
• divided into two layers:
- papillary layer - the thin superficial is areolar connective tissue and
- reticular layer - the deeper thicker is dense irregular connective tissue
• contains blood vessels, specialized sensory nerve endings, glands, hair follicles and their associated structures.
• has dermal papillae in papillary layer (meissner corpuscles)
• pacinian corpuscles
• sweat glands
dermal papillae
- in papilliary layer
* contain capillary loops, free nerve endings (pain receptors) and Meissner’s corpuscles.
Meissner’s corpuscles
are receptors that respond to light touch sensations and are most abundant in the skin of the fingertips, lips and eyelids.
: nervous tissue, tactile centers, respond to light touch
Pacinian corpuscles
- tactile receptors
- receptors are much larger than Meissner corpuscles and are located deeper in the dermis.
- Sensitive to deep pressure and occur in the skin of the fingers, in the pancreas and in the walls of the urinary bladder.
nervous tissue, tactile venter, respond to deep pressure/coarse touch
Sweat (sudoriferous) glands
- merocrine/eccrine glands
- located in the dermis
- release perspiration into hair follicles or onto the skin surface through pores.
- coiled tubular glands that secrete mostly water but also ions and some nitrogenous wastes.
- internal temp homeostats 35.8-38.2ºC
- Stim tell brain your too hot, brain signals sweat glands —> takes lots of heat to turn liquid sweat to gas. Therefore evaporative coolig mechanism.
- FUNCTION: role of sweat is to regulate body temperature through evaporation.
Hair Follicle
•hair bulb - deep end
-Sensory nerve endings (hair root plexus) wrap around the bulb and are stimulated when the hairs are bent.
•hair papilla - contains a knot of capillaries that supplies nutrients to the growing hair.
•arrector pili muscles - composed of smooth muscle tissue, are responsible for making your hair “stand on end” when you’re cold or frightened
•sebaceous gland - lubricates the skin and keeps the hair flexible
•
composed of smooth muscle tissue, are responsible for making your hair “stand on end” when you’re cold or frightened
if contracts, hair stands on end (when frightened or cold).
arrector pili muscles
contains a knot of capillaries that supplies nutrients to the growing hair
hair papilla
sebaceous gland
produce an oily secretion known as sebum, which lubricates the skin and keeps the hair flexible.
Skin disorders
- A boil (or furuncle): is a round, pus-filled, raised area of the skin caused by a bacterial infection in a hair follicle or sebaceous gland.
- Acne can develop when there is an increase in sebum production. One form of acne, often observed in adolescents, is associated with the increase in sex hormone production during puberty. As the secretory activity of sebaceous glands increases with the concentrations of hormones, an obstruction of the sebaceous ducts may result, causing inflammation and infection.
- Seborrhea, another disease of the sebaceous glands, is characterized by an excessive discharge of sebum, resulting in an oily coating or crust on the skin.
Skin colour
-influenced by the interaction of three pigments
Melanin
• Melanin formed in the deepest layers of the epidermis by cells called melanocyte
• (UV) radiation in sunlight has a stimulatory effect on the melanocytes, causing an increase in melanin pigment
• presence of melanin protects the deeper layers of the skin from the harmful effects of excessive UV
• A concentration of melanin in one spot produces a “freckle”.
Carotene
•a yellow pigment that accumulates in the surface layer of the epidermis.
Hemoglobin
• the color of the blood in the blood vessels of the dermis produces a pinkish tint
• A “flushed” appearance to the skin (reddened skin) is influenced by the degree of oxygenation of the blood in the dermal blood vessels.
• When bound to oxygen, the pigment hemoglobin is bright red in color
• when the skin is exposed to heat, small dermal blood vessels open up (dilate) and more blood flows through the dermis, producing a more pronounced “flush”.
Human Fingerprints
- ridges are due to downward projections of the epidermis into the dermis between the dermal papillae in the upper portion of the skin.
- unique to each individual
- pattern is inherited
- Fingerprints get left behind on smooth surfaces because the ducts of sweat glands open on the surface of the epidermal ridges thus leaving a “sweaty” imprint.
- FUNCTION: to increase the grip of the hand by increasing friction
Fingerprint patterns may be categorized as 3
Arch - pattern is the simplest in that the ridges rise over the middle of the finger.
Loop - pattern contains a blind-ended ridge that is surrounded by ridges that turn back on themselves.
Whorl - pattern appears as a series of concentric circles in the center, then broadens out.
When testing the ability to distinguish distinct touch sensations with calipers on various skin locations, a decrease in the distance between caliper points is associated with:
an increased density of touch receptors
Minimum Distance to Feel Two Stimuli (mm) Fingertip 2.0 Lips 5.0 Forehead 23.0 Back of Hand 31.0 Forearm 41.0
Relative Temperature Sense
EXPERIMENT
