Session 2 - Integumentary System And Nervous System Flashcards
What are the four principal tissue types?
Connective
Nervous
Epithelial
Muscle
What are the three types of epithelial tissue?
Epithelium proper
Mesothelium
Endothelium
What are the characteristics that distinguish epithelial tissue from other tissue types?
Cells are arranged to form covering sheets or lining membranes.
Cells are predominant and the amount of intercellular substance is reduced to a minimum.
What is Epithelium proper?
A lining membrane of the body tracts that open to the exterior environment.
It is found in the digestive, respiratory and urogenital tracts, exocrine glands and the epidermis
What does serous mean?
Fluid producing
What is Mesothelium?
A serous lining membrane for large cavities of the body.
Found in the pleura, pericardium and peritoneum
What type of tissue is Mesothelium?
Epithelial tissue
Where is endothelium tissue found in the body?
It lines the walls of blood and lymph vessels and the heart.
Which of the 3 epithelial tissue types is true epithelial tissue?
Epithelium proper
What is the function of epithelium proper?
It protects
What is the function of Mesothelium?
The fluid it produces reduces friction
What is the function of endothelium?
It reduces friction and helps prevent blood clotting.
What is the function of connective tissue?
It supports, protects and gives structure to other organs.
It also aids in tissue repair as it produces scar tissue to reconnect injured compartments.
What characterises connective tissue?
Individual cells are relatively far apart separated by large quantities of intercellular substance.
The quantity of fibres in intercellular substance varies
List the different types of connective tissue.
Areolar
Adipose
Dense
Cartilage
Bone
Haemopoietic
What is the function of areolar connective tissue?
It fills empty spaces between structures
What is subcutaneous adipose tissue called?
Superficial fascia
Briefly explain dense connective tissue.
It consists mainly of densely packed fibres that form elongated strands.
List examples of dense connective tissue
- Tendons
- Ligaments
- Aponeuroses
- Deep fascia
- Intermuscular septa
What is a tendon?
A tough cord composed of closely packed inelastic white fibres which connect muscles to the bone but blending in with the periosteum of bones.
What is a ligament?
Bands of dense connective tissue that join bone to bone
What is an aponeuroses?
Bands of dense connective tissue that attach flat muscle to another flat muscle or to several bones
What is deep fascia?
A fibrous sheet that intervenes between muscle and the overlying superficial fascia
What are intermuscular septa?
They pass as partitions from the deep fascia to the bone, separating groups of muscles from one another.
What are the 3 types of cartilage?
- Hyaline
- Elastic
- Fibrous
What is the general composition of bone?
It consists of a connective tissue frame,which accounts for about 1/3 of bone, that is impregnated with inorganic calcium salts, which account for about 2/3 of bone
Briefly describe haemopoietic tissue.
It forms red and white blood cells. It is found in the red marrow of long bone and in internal organs e.g. liver, spleen, and many lymph nodes.
What are the 3 types of muscle tissue?
Skeletal
Visceral
Cardiac
Briefly explain skeletal muscle tissue.
It is also called striated voluntary muscle. It is composed of long threadlike cells called muscle fibres with many cross striations. Contractions are fast of short duration. They are attached to the skeleton.
Briefly explain visceral muscle tissue.
It is also called smooth non-striated involuntary muscle. It has elongated spindle shaped cells with no striations. Contractions are slow and of longer duration. It is usually found in hollow organs.
Briefly explain cardiac muscle tissue.
It is also called striated involuntary muscle. It has branching striated calls and contractions occur rhythmically.
What are the 2 types of nervous tissue cells?
- Neurons
- Neuroglia
What are neuroglia?
Cells that form the support tissue of the nervous system. They support, insulate and nourish neurons.
What is a neuron?
Find info
What is a synapse?
A microscopic space between the terminal end of an axon and the next neuron.
What are nerve fibres?
What the axon, dendrites and their branches are collectively called.
What is a neuron?
A cell that consists of a cell body with a nucleus and one or more processes that consist of one axon and a number of dendrites.
What is an axon?
The part of the neuron the forwards impulses. It is usually a long process and has relatively few branches called collaterals.
What is a dendrite?
The part of a neuron that receives impulses. It is shorter than an axon and branches many times to form an extensive tree-like structure. The terminal end of a dendrite may be modified into a receptor that detects a specific type of stimulation e.g. touch, pressure, pain and temperature.
What is a receptor?
Find more info.
What is an effector?
Either a gland or a muscle cells that receives impulses form neurons.
Find more info.
What is a sensory (somatic afferent) neuron?
A neuron that carries impulses from the skin to the central nervous system
What is a motor (somatic efferent) neuron?
A neuron that carries motor impulses from the central nervous system to the skeletal muscles
What are somatic neurons?
Nerves that innervate those parts of the body you are aware of or which are under voluntary control. They are subdivided into afferent and efferent nerve fibres.
List the main components of the nervous system.
- Central nervous system
- Peripheral nervous system
- Autonomic nervous system
Briefly explain the central nervous system
It consists of the brain and the spinal cord, located in the cranial cavity and the vertebral canal, respectively.
Briefly explain the peripheral nervous system.
It is the principal route through which the brain and spinal cord communicate with the rest of the body. Functionally the central nervous system and the peripheral nervous system are continuous.
Briefly explain the autonomic (visceral) nervous system.
It controls the smooth and cardiac muscles, exocrine and some endocrine glands. Automomic neurons are further divided into the sympathetic and parasympathetic systems. The sympathetic nervous system dominates in stressful situations while the parasympathetic nervous system is most active in relaxed situations.
How many pairs of spinal nerves are there?
31 pairs
Give a break down of the spinal nerves.
8 pairs of cervical spinal nerves: C1 - C7
12 pairs of thoracic spinal nerves
5 pairs of lumbar spinal nerves
5 pairs of sacral spinal nerves
1 pair of coccygeal spinal nerves
Define dermatome
A unilateral area of skin innervated by sensory fibres of a spinal nerve.
Define myotome
Unilateral muscle tissue innervated by the motor fibres of a spinal nerve.
What is the sensory component of the nervous system composed of?
- General sensation - touch, pain, temperature, normal distension of a viscus stretch, ischemia
- Special sensations - vision, smell, hearing
- Proprioception - state of contraction of a muscle or position of a joint.
From which layer do somites form?
Mesoderm
Describe the formation of somites.
While the ectoderm gives origin to the neural tube and the neural crest, the mesoderm forms segments which appear as paired blocks of mesoderm, these are somites. The 2 chains of somites extend from the caudal end of the spinal cord to the brain.
What do the somites form?
The somatic structures of the body
What are the three regions that can be distinguished in developing somites?
- Dermatome - develops into the dermis of the skin
- Myotome - gives rise to skeletal muscles
- Sclerotome - forms the segmented parts of the skeleton
Name the structures that belong to the integumentary system.
- Skin and its appendages, hair, nails and mammary glands
- Superficial and deep fascia
What are the principal layers of the skin?
- Epidermis
- Dermis
What are the major functions of skin?
Find more info
Briefly explain the composition of the epidermis.
It is a superficial layer of stratified epithelium without any blood vessels. It is nourished by the underlying vascularised dermis. Its thickness depends on location.
Nails, hair follicles, sweat glands and the glandular tissue of the mammary glands are modified epidermis.
Briefly explain the composition of the dermis.
It is an underlying layer of connective tissue. Its thickness depends on location. It is thicker on dorsal/extensor surfaces than on ventral/flexor surfaces.
The dense layer of collagen and elastic fibres provide skin tone. It contains accessory structures such as blood vessels, lymphatics, nerves and receptors.
What are cleavage lines?
Also called tension lines or Langer lines are fibres in the intercellular substance of connective tissue in the dermis that have a prevailing direction in different regions of the body.
What is the consequence of lacerations or incisions that are parallel to tension lines?
Healing with little scarring
What is the consequence of lacerations or incisions across tension lines?
Healing with excessive scaring
Describe innervation of the skin
A mixed nerve consisting of afferent and efferent nerve fibres supply the skin in a segmental pattern - the dermatome.
The somatic nerve ends are sensitive for touch, pain and temperature. The sympathetic nerve fibres control vasodilation and vasoconstriction.
Describe blood supply to the skin.
Arteries to the skin form plexuses in the dermis. From these plexuses, capillary vessels originate and pass into the dermal papillae.
Classify burns in order of severity.
1st degree burn - limited to epidermis. Heals fast.
2nd degree burn - epidermis and superficial dermis are damaged and blistering occurs. It is the most painful burn as the nerve endings are damaged
3rd degree burn - entire thickness of skin and underlying muscle is damaged. Numbness is exhibited as the sensory ending is destroyed. It requires skin grafting.
What are skin ligaments?
Fibrous bands that extend through the subcutaneous tissue and attach the deep surface of the dermis to the underlying deep fascia.
Explain the muscle pump mechanism.
It is called the musculovenous pump. In the limbs, especially the lower limbs where blood must move against the pull of gravity, the deep investing fascial compartments limit the outward expansion of the bellies of contracting skeletal muscles. Blood is thus pushed out as the veins of the muscles and compartments are compressed. Valves within the veins allow the blood to flow only in one direction toward the heart.
What are the two kinds of pleura?
Parietal pleura
Visceral pleura
What is a pleura?
A sac that covers each long
What is a pleural effusion?
A collection of fluid abnormally present in the pleural space, usually resulting from excess fluid production
What is the pericardium?
A sac that covers the heart. Also called pericardial sac.
What is the peritoneum?
Also called the peritoneal sac. A sac that surrounds the abdominal viscera.
What are bursae?
Closed sacs or envelops of serous membrane that are collapsed with a thin layer of lubricating fluid
