Biology 13A – Test 2 Lecture Notes
Chapter 5 – Tissues
A. Epithelial
- Makes up linings and coverings of organs and body cavities
- Simple – single layer of cells
- Squamous – flat and tightly connected. Substances diffuse easily. E.g. lining of lungs (Fig. 5.1)
- Cuboidal – cube-shaped. Covers ducts of glands. E.g. kidney ducts (Fig. 5.2)
- Columnar – long and tightly connected.
- Ciliated – moves substances past surface. E.g. lining of ovarian ducts.
- Nonciliated – secretes or absorbs materials. E.g. lining of the digestive tract (Fig. 5.3)
- Stratified – contains many layers of cells
- Squamous – E.g. oral cavity (Fig. 5.5)
- Cuboidal – E.g. salivary glands (Fig. 5.6)
- Columnar – E.g. male urethra (Fig. 5.7)
- Glandular – specialized for secretion
- Exocrine – secretes to open surfaces. E.g. sweat gland (Fig. 5.9)
- Endocrine – secretes into tissues or blood. E.g. adrenal gland
B. Connective
a. Broad characteristics. Can provide support, protection, store fat, make up blood.
b. Types
i. Loose
1. Areolar – very delicate. Fills in spaces between muscles (Fig. 5.13)
2. Adipose – large and contains fat (Fig. 5.14)
3. Reticular – fibrous to form networks to support organs.
ii. Dense – very strong collagenous fibers. Used in tendons and ligaments (Fig. 5.15)
iii. Cartilage
1. Hyaline – tough collagenous fibers. Used in joints (Fig. 5.16)
2. Elastic – stretchable. E.g. ears (Fig. 5.17)
3. Fibrocartilage – used as shock absorbers. E.g. vertebral discs (Fig. 5.18)
iv. Bone – extremely rigid. Osteocytes are bone cells embedded in the bone. Bone grows in concentric circles (Fig. 5.19)
v. Blood (Fig. 5.20)
1. Red – carries oxygen
2. White – immune function
3. Platelets - clotting
C. Muscle
a. For movement
b. Types
i. Skeletal – voluntary. Consist of striations (Fig. 5.21)
ii. Smooth – involuntary. No striations. E.g. digestive tract (Fig. 5.22)
iii. Cardiac – involuntary. Has striations. Only found in the heart (Fig. 5.23)
D. Nervous
a. For communication
b. Cell types
i. Neurons – elongated to carry impulses long distances (Fig. 5.24)
ii. Neuroglial cells – support neurons by providing nutrients.
Chapter 6 – Integumentary System
A. Skin (Fig. 6.1)
a. Epidermis (Fig. 6.2)
i. Made from stratified squamous epithelium
ii. Cells divide and are pushed out where they die and keratinize. Forms a waterproof barrier
iii. Melanocytes exist deeper in layers and produce the skin color pigment, melanin (Fig. 6.3)
iv. Skin cancers are usually derived from this layer, e.g. squamous cell carcinoma, melanoma. (Fig. 6A)
b. Dermis
i. Made mostly from dense connective tissue
ii. Blood vessels, nerves, glands, and follicles originate here
iii. Tattoo ink remains here!
c. Subcutaneous – layer of fat beneath the skin (not considered skin)
B. Accessory Structures
a. Nails – epithelial cells containing keratin die and merge with the nail plate (Fig. 6.4)
b. Hair Follicles
i. Embedded in dermis.
ii. Similar to nails; hair cells containing keratin die and are pushed outwards. (Fig. 6.5)
iii. Goose bumps are contraction of smooth muscles around follicle
c. Glands
i. Sebaceous – oil glands associated with hair follicles. Helps protect hair and make it waterproof
ii. Sweat – secretes water to help cool the body. Some are activated under emotional changes. Mammary glands in females are modified to secrete milk.
C. Maintenance
a. Body Temperature Regulation (Fig. 1.7)
i. If too hot – skin vessels dilate, sweat glands secrete
ii. If too cold – skin vessels constrict, sweat glands do not secrete
b. Wound Healing
i. Breaking of skin promotes inflammation
1. Broken cells release chemicals such as histamine
2. Histamine causes vessel dilation. This allows more blood to the area and allows healing factors to leak out
3. Clotting and scabbing can form
4. Tissues heal, scarring (new connective tissue in dermis) can form
5. Scab falls off (if present)
ii. Tattoos are permanent because the ink is embedded in scar tissue which does not move
Chapter 7 – Skeletal System
A. Bone Structure
a. Longitudinal structures (Fig. 7.1)
i. Diaphysis is the shaft
ii. Epiphysis is the end
b. Cross section structures (Fig. 7.2, 7.3)
i. Compact bone is dense
ii. Spongy bone has gaps containing red marrow
iii. Medullary cavity contains yellow marrow, nerves, and blood vessels.
B. Functions
a. Support – strength of compact and spongy bone
b. Movement – uses lever system (Fig. 7.7)
c. Blood Cell Formation – red marrow forms blood cells (yellow is just to store fat)
d. Storage – minerals are stored and released. Blood and bone calcium levels are regulated (Fig. 7.8)
e. Bone Repair
i. There are many types of fractures (Fig. 7A)
ii. Steps in repair of a fracture (Fig. 7B)
1. Hematoma formation. Fractures result in blood leakage. This area will form a clot (hematoma).
2. Osteoblasts enter hematoma and begin to build spongy bone. Fibrocartilage is produced.
3. Bone replaces fibrocartilage.
4. Osteoclasts remove excess bone
C. Skeletal Organization
a. Skull
i. Cranium – protects the brain. 8 bones that are sutured together (Fig. 7.10)
ii. Facial – for facial movements and jaw movements. 14 bones including one movable lower jaw (Fig. 7.15)
b. Vertebral Column and Thoracic Cage
i. Vertebra – circular bones that allow nerves to pass through center. Processes allow attachment of muscles or other bones. (Fig. 7.17-19)
1. Cervical – the neck
2. Thoracic – upper back
3. Lumbar – lower back
4. Sacrum – fused vertebrae that forms a triangle (Fig. 7.20)
5. Coccyx – tailbone
ii. Thoracic Cage – protects organs
1. Ribs – attaches to thoracic vertebrae
2. Sternum – breastbone that attaches to ribs in front.
c. Pectoral and Pelvic Girdles
i. Girdles are circular and allow attachment of limbs
ii. Pectoral – supports upper limbs (Fig. 7.23)
1. Clavicles – collar bones. Attaches to scapulae.
2. Scapulae – shoulder blades. Upper limbs attach. Chest and back muscles attach.
iii. Pelvic – supports lower limbs and protects lower organs (Fig. 7.27)
1. Hip bones along with sacrum and coccyx make up the pelvis
2. The pelvic cavity is larger than in males.
d. Upper and lower limbs
i. Upper
1. Humerus – the upper arm bone. Attaches to scapula and lower arm bones (Fig. 7.24)
2. Radius – thumb side of the forearm (Fig. 7.25)
3. Ulna – pinky side of the forearm.
4. Hand bones (Fig. 7.26)
a. Carpal – wrist bones
b. Metacarpal – palm bones
c. Phalanges – fingers
ii. Lower
1. Femur – upper leg bone. Longest in body! Attaches to hip bone and two lower leg bones (Fig. 7.30)
2. Tibia – big toe side (medial) of lower leg (Fig. 7.31)
3. Fibula – pinky toe side (lateral)
4. Foot bones (Fig. 7.32)
a. Tarsal – ankle bones
b. Metatarsal – ball of foot
c. Phalanges – toes
D. Joints – joins bones together
a. Fibrous
i. No or very little movement
ii. Thin layer of dense connective tissue
iii. E.g. suture between skull bones (Fig. 7.34)
b. Cartilaginous
i. Allows slight movement. Can absorb shock
ii. Hyaline or fibrocartilage
iii. E.g. intervertebral discs
c. Synovial
i. Allows free movement
ii. Complex structure
1. Joint capsule contains ligaments that connect the bones and synovial membrane that secretes synovial fluid into center (lubricant)
2. Bone ends are surrounded by hyaline cartilage
Chapter 8 – Muscular System
A. Skeletal Muscle Structure
a. Fascia is the covering of the muscle. It extends to form the tendon which attaches to a bone (Fig. 8.1)
b. Each muscle fiber is a single cell
c. Striations are from muscle filaments that overlap (Fig. 8.3)
i. Actin filaments are thin
ii. Myosin filaments are thick
iii. Sarcomere is a functional unit
d. Neuromuscular junction
i. Motor neurons attach to motor end plate of muscle (Fig. 8.5)
ii. Space between neuron and muscle is a synapse. Neurotransmitters get released from neuron to tell muscle to contract.
B. Skeletal Muscle Contraction
a. Contraction Mechanism
i. Release of acetylcholine into synaptic cleft activates muscle
ii. Myosin binds actin and pulls towards center (Fig. 8.6)
iii. The pulling requires ATP and involves myosin heads to change shape (Fig. 8.7). Rigor mortis occurs when myosin heads are attached to actin.
iv. Fatigue can occur if lactic acid or heat builds up, especially due to anaerobic respiration (fermentation) (Fig. 8.10)
b. Muscular Responses
i. Twitch – a muscle contraction (Fig. 8.11)
1. Latent period – a delay before the contraction
2. Contraction – force is exerted
3. Relaxation – force is released
ii. Combination of twitches (Fig. 8.12)
1. Summation combines individual twitches with increasing force
2. Tetanus – sustained contraction. Muscle tone is a form of tetanus.
C. Major Skeletal Muscles
a. Facial – very superficial muscles that control facial expressions (Fig. 8.17a)
b. Mastication – for chewing. Controls jaw movements
c. Head movement – neck and back muscles allow bending and rotating the head (Fig. 8.17b)
d. Pectoral girdle – allows shoulders to move forward, back, up, and down. Also allows rotation of arm
e. Arms, legs, hands, feet – flexors and extensors are opposites. Abductors lift away from body. Rotators rotate. (Fig. 8.20-8.23, 8.25-8.30)
f. Abdominal wall – can help in exhaling, defecation, urination, vomiting, childbirth.
g. Pelvic – defecation, urination in males, vaginal contraction in females (Fig. 8.24)
Chapter 9 – Nervous System
A. Introduction
a. Nerves send information to and from the brain/spinal cord
b. The central nervous system (CNS) consists of the brain and spinal cord. Is the main controller. The peripheral nervous system (PNS) connects CNS to other body parts. (Fig. 9.2)
c. Cell types
i. Neuroglial cells – several types that support the neurons.
ii. Neurons – carry impulses (Fig. 9.4)
1. Cell body is the main body of the cell.
2. Dendrites – pick up signals from other cells.
3. Axon – long extension that transmits signal.
a. Covered in myelin sheath that acts as insulation.
b. The terminus passes signal to the next cell
B. Nerve Function
a. The synapse
i. Junction between two nerve cells (Fig. 9.9)
ii. When impulse reaches synaptic knob, neurotransmitters form in vesicles and are released into synaptic cleft.
iii. Neurotransmitters bind receptors on postsynaptic neuron
1. Excitatory neurotransmitters – cause nerve transmission
2. Inhibitory neurotransmitters – block nerve transmission (e.g. dopamine)
3. Drug Abuse
a. Cocaine – binds to dopamine reuptake transporters. Dopamine stays for too long in synaptic cleft. Is a CNS stimulant.
b. Heroin – an “opiate” that binds to opioid receptors. Is a CNS depressant.
c. LSD (lysergic acid diethylamide) – a hallucinogen that acts as an excitatory neurotransmitter for serotonin receptors.
b. Neural impulses
i. Overview (Fig. 9.15)
1. An axon has positive charges outside of membrane and negative charges inside the membrane.
2. An action potential begins by letting positive charge in through gates and this triggers adjacent gates to open. Gates behind the action potential close. This causes “the wave”
ii. Sodium (Na) and Potassium (K) control action potentials (Fig. 9.14)
1. Sodium starts out high outside, low inside. Potassium starts out high inside and low outside.
2. Sodium rushes in at the “front” of the action potential.
3. Potassium rushes out at the “back” of the action potential. This restores original charge quickly.
4. Gates change their shapes (Fig. 9.11). They close and cannot be opened for a brief period (refractory period).
iii. Initiation of the impulse (Fig. 9.13)
1. Neurotransmitters bind receptors and trigger influx of sodium into cell body.
2. This triggers sodium gates at beginning of axon to open.
3. Intensity of impulse is always the same. When “on” it is fully turned on. This is called “all-or-none”.
C. Parts of the Nervous System
a. Brain
i. Cerebrum
1. Structure
a. Left and right hemispheres (Fig. 9.27)
b. 5 lobes (Fig. 9.28)
2. Functions
a. Motor – movements
b. Sensory – all five senses are processed here
c. Association – link different functions together. Involved in memory, reasoning, judgment, verbal skills, and emotion.
ii. Diencephalon – processes sensory information
iii. Brainstem – connects the cerebrum to the spinal cord. Regulates visceral activities like heart rate, vessel contraction, and breathing.
iv. Cerebellum – helps in coordination, equilibrium, complex muscle movements
b. Spinal Cord (Fig. 9.23)
i. Nerve impulse conduction
1. Ascending tracts allow for sensory information to go to brain (Fig. 9.25)
2. Descending tracts allow for motor information to be sent out to muscles and glands (Fig. 9.26)
ii. Spinal reflexes
1. Patellar – “knee jerk”. Only two neurons involved. Important in posture (Fig. 9.19)
2. Withdrawal – “pullback”. Three neurons involved. Reaction to pain or heat (Fig. 9.20)
c. Peripheral Nerves
i. Cranial
1. Arises from under the brain (Fig. 9.34)
2. Communicates to head, neck, trunk
ii. Spinal
1. Originate from spine and travel outwards (Fig. 9.35)
2. Communicates to limbs, neck, and trunk
D. Autonomic Nervous System
a. Part of the PNS that functions without conscious effort.
b. Types
i. Sympathetic – active during emergency situations or “fight-or-flight” response.
ii. Parasympathetic – active during normal conditions. Restores body back from sympathetic response
c. Some examples of activities are changes in heart rate, blood distribution, glucose concentration in blood (Tab. 9.7)