Midterm 2 Flashcards
Body cavities
- Dorsal
- cranial (head cavity- brain)
- vertebral (spinal cord) - Ventral
- thoracic (chest) - pericardial (heart), pleural (lungs)
- abdominal (digestive organs)
- pelvic (urinary bladder, reproductive organs, rectum)
What are body cavities
Enclosed spaces that house and protect organs
Organs
Consist of 2 or more major tissue types (some can consist of all 4)
- epithelial
- connective
- nervous
- muscle
Membranes
- line cavities
- consist of 1 or 2 tissue types (connective tissue with or without attached epithelial tissue)
- line inner and outer surfaces of the body and its organs
Mucous membranes
- lines cavities and organs that open directly to body exterior
- found in the digestive respiratory, urinary and reproductive systems
1. Epithelial layer - in contact with lumen of organ
- avascular
- many have goblet cells
- lots of vili
- lines digestive tract
2. Lamina propria - connective tissue layer that connects epithelial tissue to wall of organ
- loose areolar tissue
- vascular
- nourishes epithelial cells
Serous membrane
- lines body cavities and organs that don’t open up to outside of body
- cover external surfaces of organs in these cavities
- double layered, layers composed of a simple epithelium bound to an areolar connective tissue
1. Parietal layer: against cavity wall
2. Visceral layer: against organ - epithelial layers secrete serous fluid into the serous cavity
- locations:
1. Pericardium (heart)
2. Pleura (lungs)
3. Peritoneum (abdominal organs)
Synovial membrane
- in joints
- areolar connective tissue
- no epithelium
- only one tissue type, therefore, NOT an organ
Cutaneous membrane
Skin:
- epithelium: stratified squamous (named the epidermis)
- connective tissue: areolar and dense irregular (named the dermis)
Integumentary system
main function = protection
Consists of:
- skin
- nails, hair, glands
- muscles (goosebumps)
- sense receptors (nervous)
- hypodermis
Skin
- Epidermis
- Dermis
- Hypodermis (below skin)
Epidermis of skin
- stratified squamous epithelium
- avascular
- sub layers:
1. Stratum basale
2. Stratum spinosum
3. stratum granulosum
4. Stratum lucidum
5. Stratum corneum
Stratum basale of epidermis
- single row of cells
- 2 cell types:
1. Keratinocytes (90% of skin) - undergo mitosis (shedding skin)
- makes keratin (tough protein)
- pushed towards surface as new cells are produced in basale
2. Melanocytes (10% of skin) - produce pigment for UV light protection
- skin colour (cells produce different amounts and shades of melanin)
Stratum spinosum of epidermis
- low levels of mitosis
Stratum granulosum of epidermis
- last layer of living cells
- no mitosis
- contains granules that help produce keratin and start to produce water proofing glycolipids to prevent water loss
Stratum lucidum of epidermis
- only found in thick skin
- first layer of dead cells
- no mitosis
- flat, dead cells (too far from blood supply)
Stratum corneum of epidermis
- many layers of flat, dead cells filled with keratin
- glycolipids between cells creates a waterproof layer to prevent water loss
- shed and replaced from below
Dermis of skin
- contains blood vessels, nerves, glands, hair follicles, and arrest or pili muscles
- 2 sub-layers (connective tissue):
1. Papillary layer
2. Reticular layer
Papillary layer of dermis
- connected to epidermis
- areolar connective tissue
- vascular
- has projection into epidermis = dermal papillae (in thick skin these form epidermal ridges like fingerprints to improve grip)
Reticular layer of dermis
- between papillary layer and hypodermis
- forms most of dermis
- dense irregular connective tissue
- tears in collagen in reticular layer lead to the look of stretch marks
Thickness of skin
Refers to the epidermis not the dermis
Thin skin
- covers most of body
- lucidum absent
- has hair follicles, sebaceous glands and arrest or pili muscles
Thick skin
- found on the palm of hand and the sole of the foot
- lucidum present
- no hair follicles, sebaceous glands or arrector pili muscles
Epidermal derivatives
All derived (formed) from the epidermis
Include:
1. Hair
2. Nails
3. Skin exocrine glands
Hair
- all dead cells
- root = part of hair embedded in the skin
- shaft = visible part of hair above the skin surface
- hair follicle = surrounds root
- epithelial root sheath = several epidermal layers extended into the dermis
- bulb = expanded region at base of root
- matrix = single layer of cells (site of hair growth and melanin for hair colour)
- Outer CT sheath = holds follicle in placed
- hair papilla = extends upwards beneath matrix and contains blood supply for growing hair
- root hair plexus = free nerve ending
- sebaceous gland = opens into follicle
- arrector pili muscle = causes goosebumps
Nails
- heavily keratinized epidermal cells
- consists of: nail root, body and free edge
Skin exocrine glands
- Sebaceous gland
- Sudoriferous gland
- Ceruminous gland
- Mammary gland
Sebaceous gland
- connected mainly to hair follicle
- secrets sebum (oil)
- softens, lubricates hair and skin, prevents drying out, antibiotic
Sudoriferous glands
- sweat glands
- secretory portions in dermis of thick and thin skin
- ducts open onto skin surface
- temperature regulation: cool the body
- antibiotic action: due to sweat being acidic
- waste removal: urea
Ceruminous glands
- modified sweat glands
- in ear canal
- produce ear wax (prevents insects, etc. from entering)
Mammary glands
- modified sweat glands
- produce milk
Sense receptors
- sensory neurons (part of nervous system)
- specialized cell that responds to stimuli
- 4 major types:
1. Touch receptors
2. Pressure receptors
3. Thermoreceptors
4. Nociceptors
Touch receptors
- most major
- free nerve endings (in epidermis)
- root hair plexus
- tactile (Meissner’s) corpuscles (found under epidermis: in dermal papillae, corpuscle is a CT capsule surrounding a nerve ending
Pressure receptors
- free nerve endings (in dermis)
- Lamellar (pacinian) corpuscles (looks like onion through microscope: deep in dermis or hypodermis
Thermoreceptors
Free nerve endings for temperature
Nociceptors
- free nerve ending for pain
- 3rd degree burns destroy Nociceptors, causing lack of pain sensation in affected areas
- 1st and 2nd degree burns hurt more because Nociceptors are still intact
Hypodermis
- not a part of the skin
- also called the subcutaneous layer
- also called superficial fascia (fascia: CT layers that surround and support organs)
- adipose CT below skin that stores 1/2 of body’s adipose tissue (insulation, fat)
Medical conditions - integumentary system
- Albinism= lack of melanin production by melanocytes
- Psoriasis= autoimmune disorder that causes accelerated mitosis of keratinocytes in the stratum basale
- accelerated cell cycle delays maturation and differentiation of keratinocytes
- immature keratinocytes accumulate in the epidermis and stratum corneum fails to shed, resulting in a thick, scaly area on the surface of the skin
Bone
- tissue AND organ
- 2 types:
1. Compact bone
2. Spongy bone
Compact bone
- covers external surfaces of all bones
- structure: composed of osteons (made of 3 rings)
- osteons contain:
1. Lamellae- concentric circles of matrix
2. Lacunae- between lamellae (space within matrix where osteocytes live)
3. Canaliculi- small channels that connect osteocytes to blood supply and to each other
4. Central canal- contains blood vessels and nerves, lined with endosteum
5. Perforating canal- perpendicular to central canal, carries blood and nerve supply from periosteum to canals and medullary cavity
Spongy bone
- No osteons
- have holes where blood cells are generated
- have trabeculae- irregularly arranged lamellae (similar to osteons)
- canaliculi connect octeocytes in lacunae
- spaces contain bone marrow (red marrow produces blood cells)
- found in:
1. Flat and irregular bone (skull, ribs, vertebrae)
2. Long bones (epiphyses- looks like an aero bar and lining medullary cavity- middle cavity)
Skeleton
- Axial skeleton: bones that form from central core of body
- Appendicular skeleton: limbs and bones that attach them to axial skeleton (girdles)
Articulations
- connections between bones
- region where 2 bones are connected
Axial skeleton
- Skull
- Hyoid bone
- Vertebral column
- Thoracic cage
Appendicular skeleton
- Pectoral girdle
- Pelvic girdle
- Upper limb
- Lower limb
Components of long bones
- Diaphysis- shaft (body)
- Epiphysis- proximal and distal extremities
- Epiphyseal plate- hyaline cartilage, used for bone growth (length)
- Epiphyseal line- replaces plate when bone growth is complete, plate/line where the diaphysis and epiphysis meet
- Medullary cavity- red bone marrow in child, yellow bone marrow in adult
- Periosteum- external surface, 2 layers of CT (outer= dense irregular, inner= mainly osteoblasts and osteoclasts), allows bone to grow in diameter
- Endosteum- lines medullary cavity and canals
- Articulated cartilage- hyaline (only at articulation points, prevents friction between bones
Fibrous structural joints
- no joint cavity
- fibrous CT
- ex. Sutures in skull
Cartilaginous structural joints
- no joint cavity
- cartilage attaches bones
- ex. Pubic symphysis, costal cartilages of ribs
Synovial structural joints
- articulating bones are connected by the joint capsule and ligaments
- articulating cartilage (hyaline) of bone
- space between bones is the joint cavity (contains synovial fluid)
- articular/joint capsule encloses the joint cavity (outer layer= fibrous capsule and attaches to periosteum, inner layer= synovial membrane and secretes synovial fluid
Types of synovial joints
- according to shape of articulating bones
1. Plane/gliding= 2 flat surfaces moving past each other (ex. Sacroiliac)
2. Hinge= concave and convex surfaces (ex. Elbow and knee)
3. Pivot= projection in ring
4. Ball and socket= great freedom of movement (ex. Humerus in glenoid fossa and femur in acetablum)
Functional joints
- based on degree of movement
Synarthrotic functional joints
- immovable
- ex. Skull sutures
Amphiarthrotic functional joints
- slightly moveable
- ex. Pubis bone
Diarthrotic functional joints
- freely moveable
- ex. Hip, shoulder
Muscular system
- refers to skeletal muscle system
- primarily attaches muscle to bone
- produce movement by contracting
- very important in locomotion and maintaining body posture
Skeletal muscle
- cells called fibres
- fascicle= group of fibres
- whole muscle= group of fascicles
Fascia
- CT surrounding muscles or other organs
1. Epimysium- surrounds entire skeletal muscle
2. Perimysium- surrounds fascicles within skeletal muscle
3. Endomysium- surrounds each muscle fibre (cell) within skeletal muscle