Post on 04-Jun-2018
Migration of
the
Conceptus
The egg is
fertilized in the
distal end of the
uterine tube, and
the pre-embryo
begins cleavage as
it migrates to the
uterus.
Ovary
Maturing
follicle
Corpus
luteum
Ovulation
Secondary
oocyte
First polar
body
Sperm Cell
Fertilization
(0 hours)
Zona
pellucida
Sperm
pronucleus
Egg
pronucleus
Second polar
body
*Zygote
Cleavage
Blastomeres
2-celled stage
(30 hours)
4-celled stage
8-celled stage
Morula (72
hours)
Blastocyst
Implanted
blastocyst
(6 days)
Ectoderm
Mesoderm
Mesoderm
Structure of
the skin and
subcutaneous
tissue.
Dermal Papilla responsibly for exchange of oxygen, nutrients and waste products between the dermis and
the epidermis. *Provides hair with its sole source of nutrition.
Tactile Corpuscle (touch receptor nerve ending in the skin that is responsible for sensitivity to light touch. In particular, they
have highest sensitivity (lowest threshold) when sensing vibrations lower than 50 Hertz.
They are rapidly adaptive receptors.
Blood Capillaries provide oxygen and nutrients to the cells of the body and remove carbon dioxide and
waste materials.
Hair Follicle A hair follicle is a mammalian skin organ that produces hair. Hair production occurs in
phases, including growth (anagen), cessation (catagen), and rest (telogen) phases. Stem
cells are responsible for hair production.
Sebaceous gland Produce an oily secretuion called sebum. *Oil producing gland associated with hair follicles
Hair receptor Entwine each follicle and respon to hair movements
Apocrine Sweat gland Produce secretion by exocytosis. Scent glands that respond especially to stress and sexual
stimulation. *Secrete sex phermones.
Hair bulb Forms the base of the hair follicle. In the hair bulb, living cells divide and grow to build the
hair shaft. Blood vessels nourish the cells in the hair bulb, and deliver hormones that
modify hair growth and structure at different times of life.
Sensory Nerve fibers
Piloerector muscle (arrector pili) In response to cold, fear, touch, or other stimulii, the SNS (sympathetic Nervous system)
stimulates this muscle to make the hair stand.
Lamellated (pacinian) They are nerve endings in the skin responsible for sensitivity to pain and pressure.
Corpuscle (pressure receptor) They are a type of nerve ending in the skin that is responsible for sensitivity to light touch.
In particular, they have highest sensitivity.
Motor nerve fibers The motor nerve fibers help stimulate the Erector pili muscle.
Cutaneous blood vessels
Merocrine sweat gland Sweat glands that function in evaporative cooling; widely distributed over the body
surface; open by ducts onto the skin surface.
Hypodermis (subcutaneous fat) It consists of mostly adipose tissue and is the storage site of most body fat. It serves to
fasten the skin to the underlying surface, provides thermal insulation, and absorbs shocks
from impacts to the skin.
Dermis The dermis regulates temperature and supplies the epidermis with nutrient-saturated blood. It
contains most of the skin's specialised cells and structures such as blood vessels, hair follicles, nerve
endings, lymph vessels and sweat glands.
Epidermis acts as the body's major barrier against an inhospitable environment, by preventing pathogens from entering, making the skin a natural barrier to infection.
Sweat pores sweat pores is actually to cool your body. When you're too hot your body releases sweat
as an attempt to cool you down. This is the primary function of sweat pores.
Hair Hair provides thermal regulation and camouflage for many animals; for others it provides
signals to other animals such as warnings, mating, or other communicative displays; and
for some animals hair provides defensive functions and, rarely, even offensive protection.
Hair also has a sensory function, extending the sense of touch beyond the surface of the
skin. Guard hairs give warnings that may trigger a recoiling reaction.
Strata and
cell types of
the Epidermis
Epidermal Layers:
Stratum corneum
Strum lucidium
stratum granulosum
Stratum spinosum
Stratum Basale
Dermal Layers:
Dermis
Papillary
Recticular
Hypodermis Layer:
Only one and called
the Hypodermis or
Subcutaneous